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1
Berveglieri, Adilson. "Classificação fuzzy de vertentes por krigagem e TPS com agregação de regiões via diagrama de Voronoi /." Presidente Prudente : [s.n.], 2011. http://hdl.handle.net/11449/88156.
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Orientador: Messias Meneguette JúniorBanca: João Fernando Custodio da Silva
Banca: Ricardo Luís Barbosa
Resumo: As vertentes, como superf cies inclinadas, consistem em express~oes da Geomorfologia moldadas por fatores naturais (end ogenos e ex ogenos) e pelo pr oprio homem. Suas formas determinam o uxo ou o ac umulo de agua e representam caracter sticas fundamentais para a preven c~ao e resolu c~ao de problemas associados ao relevo, tais como utiliza c~ao do solo, constru c~ao civil entre outros. A classi ca c~ao da vertente em c^oncava, convexa ou retil - nea permite a identi ca c~ao de areas conforme sua declividade. Assim, por meio de uma grade retangular regular, base do modelo digital de terreno, gera-se uma malha interpolada por fun c~oes estimadoras: thin-plate spline, que possui caracter sticas de suaviza c~ao e krigagem, que al em da suavidade tamb em considera a depend^encia espacial. Logo ap os, a classi ca c~ao e feita, obedecendo a infer^encia fuzzy baseada em fun c~oes de pertin^encia que de nem classes a partir do c alculo da inclina c~ao e da concavidade ou convexidade do terreno. Entretanto, o resultado dessa classi ca c~ao est a atrelado a resolu c~ao da malha, n~ao permitindo fazer qualquer corre c~ao pontual. Pois, pequenas areas de pouca signi c^ancia podem ser formadas, necessitando elimin a-las. Nesse sentido, para que o resultado seja ajustado, aplica-se o diagrama de Voronoi, caracterizado por sua rela c~ao de abrang^encia e proximidade, como ferramenta para agregar regi~oes anteriormente classi cadas de modo a permitir um ajuste local e tornar o resultado mais condizente com a area em estudo, quando comparada a mapas geomorfol ogicos correspondentes
Abstract: Slopes, such as inclined surfaces, consist in geomorphological expressions shaped by natural factors (endogenous and exogenous) and also by man himself. Their shapes determine the ow or accumulation of water and represent fundamental characteristics for the prevention and resolution of problems associated with relief, as land use, buildings, and others. Classi- cating slopes in concave, convex or straight allows to identi cate areas based on declivity. Thus, by regular rectangular grid which represents a digital terrain model, it generates a interpolated mesh by estimator functions: thin-plate spline, which has characteristics of smoothing, and kriging, which besides smoothing also considers spatial dependence. After that, the classi cation is realized according to fuzzy inference based on membership functions that de ne classes from the calculation of the slope and concavity or convexity of the ground. However, the classi cation depends on mesh resolution and it not allows any point correction. Once small areas with little importance can be formed requiring eliminate them. In order to adjust the result, it applies the Voronoi diagram, characterized by its comprisement and close relationship and scope, as a tool to aggregate regions previously classi ed and allow a local adjustment, that can provides a consistent result in study areas, if it was compared to the corresponding geomorphological maps
Mestre
2
Kidner, David B. "Digital terrain models for radio path loss calculations." Thesis, University of South Wales, 1991. https://pure.southwales.ac.uk/en/studentthesis/digital-terrain-models-for-radio-path-loss-calculations(6733f679-d3c0-4a25-916f-0464321ea520).html.
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This work addresses the problem of digital terrain modelling for estimating radio path propagation within a mobile communication system. The ideal requirements are for a data structure which is storage efficient and computationally efficient for calculating profiles, whilst elevation errors should be constrained and radio path loss errors should be minimised. For a digital terrain model (DTM) to be considered viable as an alternative to the regular grid, it should: (i) produce a storage saving of at least 75% over the regular grid; (ii) be error constrained to a maximum absolute error of 10 metres; (iii) produce only a small overall average elevation error; (iv) preserve critical terrain characteristics such as ridges, peaks and slopes; (v) produce 95% of profiles to within a radio path loss error of ± 6 decibels; and (vi) be as computationally efficient as the regular grid. This research focuses on the implementation of a number of prototype DTMs, including a regular grid, sub-sampled grids, variable density grids, elevation difference grids, polynomial models of fixed and variable degree, surface patch quadtrees, and triangulated irregular networks (TINs). Each of these DTMs are examined in terms of the criteria outlined above. No DTM fulfils all of these requirements. The user should identify the relative importance of each requirement before selecting a specific model. For this study, computational efficiency is identified as the criterion which can be considered the least important. With this in mind, two original DTMs are developed. These are optimised with respect to storage and error constraints. The proposed Huffman-encoded DTM represents the deviations of a regular grid of heights from linearly predicted values as variable-length codes, whilst the Implicit TIN is a storage-efficient triangulated irregular network which reconstructs the original topology of the triangulation at the application stage. Both methods produce storage savings approaching 90% over the regular grid for the data sets tested and are suitable for parallel implementations.
3
Terei, Gabor. "A thorough investigation of digital terrain model generalization using adaptive filtering /." The Ohio State University, 2000. http://rave.ohiolink.edu/etdc/view?acc_num=osu1488193272068463.
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4
Fabian, Christopher J. "Application of a digital terrain model for forrest land classification and soil survey." Diss., Columbia, Mo. : University of Missouri-Columbia, 2004. http://hdl.handle.net/10355/4107.
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Thesis (M.S.) University of Missouri-Columbia, 2004.The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file viewed on (June 30, 2006). Vita. Includes bibliographical references.
5
Hartshorne, James Byng. "Assessing the influence of digital terrain model characteristics on tropical slope stability analysis." Thesis, University of Bristol, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.336822.
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Gillin, Cody Palmer. "Digital terrain analysis to predict soil spatial patterns at the Hubbard Brook Experimental Forest." Thesis, Virginia Tech, 2013. http://hdl.handle.net/10919/50818.
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Topographic analysis using digital elevation models (DEMs) has become commonplace in soil and hydrologic modeling and analysis and there has been considerable assessment of the effects of grid resolution on topographic metrics using DEMs of 10 m resolution or coarser. However, examining fine-scale (i.e., 1-10 m) soil and hydrological variability of headwater catchments may require higher-resolution data that has only recently become available, and both DEM accuracy and the effects of different high-resolution DEMs on topographic metrics are relatively unknown. This study has two principle research components. First, an error analysis of two high-resolution DEMs derived from light detection and ranging (LiDAR) data covering the same headwater catchment was conducted to assess the applicability of such DEMs for modeling fine-scale environmental phenomena. Second, one LiDAR-derived DEM was selected for computing topographic metrics to predict fine-scale functional soil units termed hydropedological units (HPUs). HPU development is related to topographic and surface/subsurface heterogeneity resulting in distinct hydrologic flowpaths leading to variation of soil morphological expression. Although the two LiDAR datasets differed with respect to data collection methods and nominal post-spacing of ground returns, DEMs interpolated from each LiDAR dataset exhibited similar error. Grid resolution affected DEM-delineated catchment boundaries and the value of computed topographic metrics. The best topographic metrics for predicting HPUs were the topographic wetness index, bedrock-weighted upslope accumulated area, and Euclidean distance from bedrock. Predicting the spatial distribution of HPUs may provide a more comprehensive understanding of hydrological and biogeochemical functionality of headwater systems.Master of Science
7
Jordan, Gyözö. "Terrain Modelling with GIS for Tectonic Geomorphology : Numerical Methods and Applications." Doctoral thesis, Uppsala universitet, Miljö- och landskapsdynamik, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-4635.
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Analysis of digital elevation models (DEMs) by means of geomorphometry provides means of recognising fractures and characterising the morphotectonics of an area in a quantitative way. The objective of the thesis is to develop numerical methods and a consistent GIS methodology for tectonic geomorphology and apply it to test sites. Based on the study of landforms related to faults, geomorphological characteristics are translated into mathematical and numerical algorithms. The methodology is based on general geomorphometry. In this study, the basic geometric attributes (elevation, slope, aspect and curvatures) are complemented with the automatic extraction of ridge and valley lines and surface specific points. Evan’s univariate and bivariate methodology of general geomorphometry is extended with texture (spatial) analysis methods such as trend, autocorrelation, spectral, wavelet and network analysis. Digital terrain modelling is carried out by means of (1) general geomorphometry, (2) digital drainage network analysis, (3) digital image processing, (4) lineament extraction and analysis, (5) spatial and statistical analysis and (6) DEM specific digital methods such as shaded relief models, digital cross-sections and 3D surface modelling. Geological data of various sources and scales are integrated in a GIS database. Interpretation of multi-source information confirmed the findings of digital morphotectonic investigation. A simple shear model with principal displacement zone in the NE-SW direction can explain most of the morphotectonic features associated with structures identified by geological and digital morphotectonic investigations in the Kali Basin. Comparison of the results of the DTA with the known geology from NW Greece indicated that the major faults correspond to clear lineaments. Thus, DTA of an area in the proposed way forms a useful tool to identify major and minor structures covering large areas. In this thesis, numerical methods for drainage network extraction and aspect analysis have been developed and applied to tectonic geomorphology.
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Heliani, Leni Sophia. "Determination of the Indonesian gravity fields from combination of surface gravity, satellite altimeter and digital terrain model data." 京都大学 (Kyoto University), 2003. http://hdl.handle.net/2433/149084.
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Galindo, José Roberto Fernandes. "Análise da reconstrução 3D a partir de um par estereoscópico HR-CCD/CBERS-2 usando dois modelos matemáticos /." Presidente Prudente, 2008. http://hdl.handle.net/11449/86785.
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Resumo: Desde o advento dos primeiros satélites de Sensoriamento Remoto, vários são os estudos desenvolvidos com o intuito de utilizar as imagens produzidas por estes sensores para fins cartográficos. Apesar das imagens de baixa e média resolução não possuírem a precisão requerida para aplicações cartográficas em escalas grandes, existem vantagens como: serem imagens multiespectrais, possuírem periodicidade e menores custos para a sua aquisição, quando comparadas com as obtidas através dos tradicionais levantamentos aerofotogramétricos. Uma melhoria presente nos satélites de alta e média resolução é a capacidade de visada off nadir, o que permite à formação de pares estereoscópicos e a reconstrução 3D da cena imageada, a geração de modelos digitais de elevação (MDE) e a produção de imagens ortorretificadas, dentre outros produtos. Com os primeiros pares estereoscópicos adquiridos pelo sensor HR-CCD (High Resolution Charge-Coupled Devices) do CBERS-2 (2004), surgiu a possibilidade de realizar estudos objetivando a geração de produtos cartográficos a partir desses estereopares... (Resumo completo, clicar acesso eletrônico abaixo)Abstract: Since the advent of the first Remote Sensing satellites, many studies have been developed with the intention of using the images produced by these sensors for cartographic purpose. Although these images of the average resolution do not possess the accuracy required for cartographic applications in big scales, their advantages include being multispectral, periodic repetition of acquisition, and lower cost when compared to images obtained through traditional aerial photogrammetric surveys. An improvement present in medium and high resolution satellites is their off nadir capacity, which allows 3D reconstruction based on stereoscopy, the generation of digital elevation models (DEM) and the production of orthorectified images, among others products. With the first stereoscopic pairs acquired by the CBERS-2 (2004) HR-CCD (High Resolution Charge-Coupled Device) sensor, the possibility now exists of realizing studies whose goal is generating cartographic products from these stereo pairs. Within this context, this work evaluated the geometric quality of a CBERS-2 HR-CCD stereo pair making use of the DLT (Direct Linear Transformation) mathematical model and Polynomial-Based Pushbroom model, available from the Leica Photogrammetry Suite (LPS) digital photogrammetry system by Leica Geosystems, classifying them in accordance with the Cartographic Accuracy Standards... (Complete abstract click electronic access below)
Orientador: Júlio Kiyoshi Hasegawa
Coorientador: Maurício Galo
Banca: João Fernando Custódio da Silva
Banca: Hideo Araki
Mestre
10
McKeon, Sean Patrick. "A GPU Stream Computing Approach to Terrain Database Integrity Monitoring." Digital Archive @ GSU, 2009. http://digitalarchive.gsu.edu/cs_theses/65.
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Synthetic Vision Systems (SVS) provide an aircraft pilot with a virtual 3-D image of surrounding terrain which is generated from a digital elevation model stored in an onboard database. SVS improves the pilot's situational awareness at night and in inclement weather, thus reducing the chance of accidents such as controlled flight into terrain. A terrain database integrity monitor is needed to verify the accuracy of the displayed image due to potential database and navigational system errors. Previous research has used existing aircraft sensors to compare the real terrain position with the predicted position. We propose an improvement to one of these models by leveraging the stream computing capabilities of commercial graphics hardware. "Brook for GPUs," a system for implementing stream computing applications on programmable graphics processors, is used to execute a streaming ray-casting algorithm that correctly simulates the beam characteristics of a radar altimeter during all phases of flight.
11
Höfler, Veit, Christine Wessollek, and Pierre Karrasch. "Modelling prehistoric terrain Models using LiDAR-data: A geomorphological approach." SPIE, 2015. https://tud.qucosa.de/id/qucosa%3A35056.
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Terrain surfaces conserve human activities in terms of textures and structures. With reference to archaeological questions, the geological archive is investigated by means of models regarding anthropogenic traces. In doing so, the high-resolution digital terrain model is of inestimable value for the decoding of the archive. The evaluation of these terrain models and the reconstruction of historical surfaces is still a challenging issue. Due to the data collection by means of LiDAR systems (light detection and ranging) and despite their subsequent pre-processing and filtering, recently anthropogenic artefacts are still present in the digital terrain model. Analysis have shown that elements, such as contour lines and channels, can well be extracted from a highresolution digital terrain model.
This way, channels in settlement areas show a clear anthropogenic character. This fact can also be observed for contour lines. Some contour lines representing a possibly natural ground surface and avoid anthropogenic artefacts. Comparable to channels, noticeable patterns of contour lines become visible in areas with anthropogenic artefacts. The presented work ow uses functionalities of ArcGIS and the programming language R.¹ The method starts with the extraction of contour lines from the digital terrain model. Through macroscopic analyses based on geomorphological expert knowledge, contour lines are selected representing the natural geomorphological character of the surface. In a first step, points are determined along each contour line in regular intervals. This points and the corresponding height information which is taken from an original digital terrain model is saved as a point cloud. Using the programme library gstat, a variographic analysis and the use of a Kriging-procedure based on this follow.
The result is a digital terrain model filtered considering geomorphological expert knowledge showing no human degradation in terms of artefacts, preserving the landscape-genetic character and can be called a prehistoric terrain model.
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Persson, Karin. "Visualisering av strandlinjens läge kring Hammersta ruin i Nynäshamns kommun 500‒1500 e.Kr." Thesis, Stockholms universitet, Institutionen för naturgeografi och kvartärgeologi (INK), 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-74264.
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För ca 11 500 år sedan började Weichselisen smälta bort från Stockholmsregionen och trycket som ismassan utövade på jordskorpan började sakta lätta. Sedan dess har markytan inom de tidigare istäckta områdena arbetat för att återfå sitt jämviktsläge. Detta har påverkat strandlinjens läge genom en kombination av den pågående isostatiska återhämtningen och den varierande eustatiska förändringen. Denna uppsats fokuserar på ett område i anslutning till Hammersta ruin ca 13 km norr om Nynäshamn. Strandlinjerna för perioden 500–1500 e.Kr. har beräknats genom att strandlinjenivåer för varierande tidpunkter mellan 7000–3850 f.Kr. använts som utgångspunkt. Dessa individuella strandlinjenivåer har med hjälp av ett andragradspolynom sammanbundits med ett 0-värde motsvarande havsnivån för höjdsystemet RH70. Strandlinjenivåerna för denna studie har därefter kunnat läsas avfrån den resulterande regressionskurvan. Regressionskurvan är således inte en strandförskjutningskurva i bemärkelsen strandlinjens kontinuerliga utveckling över tid, utan snarare ett sätt att interpolera värden för aktuella undersökta tidpunkter utifrån befintliga höjdvärden före och därefter. För visualisering av strandlinjernas läge har därefter höjddatasetet bearbetats i ArcGIS för att få en markyta överensstämmande med perioden mellan 500 och 1500 e.Kr. i 100-års intervall. Moderna landformer som vägar, diken och åfåror har uteslutits för att undvika att dessa påverkar strandlinjernas lägen och form i terrängen. Resultaten blev 11 kartbilder för omgivningen kring ruinen samt fyra kartbilder för ruinens närområde. Dessa visar var och en på strandlinjens läge vid en viss tidpunkt med en högsta nivå 0,87 m högre för strandlinjen under året. Denna baserades på vattenståndsmätningar från SMHI för åren 1889–2010 vid Skeppsholmen i Stockholm. De framställda kartbilderna kan återfinnas i kapitel 7, på http://ww2.ink.su.se/living_maps/hammersta samt i bilaga 3. Ön som ruinen är belägenpå blev en del av Södertörn ca 1400 e.Kr.
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Pegler, Kevin Huntly. "An examination of alternative compensation methods for the removal of the rid[g]ing effect from digital terrain model data files." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape9/PQDD_0020/MQ54638.pdf.
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Čička, Peter. "Využití programových prostředků GIS a CAD pro tvorbu digitálního modelu terénu." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2014. http://www.nusl.cz/ntk/nusl-227119.
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Master thesis is focused on formation of digital terrain model. The aim of work is to become acquainted with a dilemma in regard to terrain formation theory from the very beginning of data gathering process up to landscape digital model creation of interested area. The result of thesis is to compare advantages and disadvantages of particular programs destined for 3D modelling (ArcGIS, AutoCAD, Atlas DMT, Microstation, Catia, SolidWorks) in relation to geodetics and geoinformatics.
15
Silva, Cláudia Alexandra Fernandes. "Dinâmica sedimentar em sistemas dunares litorais. Aplicação ao sistema dunar da praia do Guincho, Cascais." Master's thesis, ISA/UL, 2015. http://hdl.handle.net/10400.5/11160.
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Mestrado em Arquitectura Paisagista - Instituto Superior de AgronomiaThe Guincho's beach dune system is part of a larger system, called Guincho-Oitavos's dune system. This is one of the most remarkable wind corridors of the European continent, and is extremely important for our natural heritage. However, the anthropogenic activity has been causing changes in its natural evolution process, destabilizing it. In this dissertation it's analyzed the development of Guincho's beach dune system in recent years, and it's also developed a theoretical exercise that estimates its possible future development, based on its evolution pattern and on the premise that the inherent conditions for their development remain constant over time. Thus, its possible to suggest sustainable management measures allowing the development of its dynamic behavior in accordance with the surrounding elements, preserving its particular characteristics and biodiversity, as well as its potential as a natural heritage and recreational space
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Staats, Wesley A. "USE OF LIDAR-DERIVED TERRAIN AND VEGETATION INFORMATION IN A DECIDUOUS FOREST IN KENTUCKY." UKnowledge, 2015. http://uknowledge.uky.edu/forestry_etds/24.
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The use of Light Detection and Ranging (LiDAR) information is gaining popularity, however its use has been limited in deciduous forests. This thesis describes two studies using LiDAR data in an Eastern Kentucky deciduous forest. The first study quantifies vertical error of LiDAR derived digital elevation models (DEMs) which describe the forests terrain. The study uses a new method which eliminates Global Positioning System (GPS) error. The study found that slope and slope variability both significantly affect DEM error and should be taken in to account when using LiDAR derived DEMs. The second study uses LiDAR derived forest vegetation and terrain metrics to predict terrestrial Plethodontid salamander abundance across the forest. This study used night time visual encounter surveys coupled with zero-inflation modeling to predict salamander abundance based on environmental covariates. We focused on two salamander species, Plethodon glutinosus and Plethodon kentucki. Our methods produced two different best fit models for the two species. Plethodon glutinosus included vegetation height standard deviation and water flow accumulation covariates, while Plethodon kentucki included only canopy cover as a covariate. These methods are applicable to many different species and can be very useful for focusing management efforts and understanding species distributions across the landscape.
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Marconato, Renata. "Análise do custo de transporte de fertilizantes com uso de modelagem digital de terreno." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/3/3138/tde-04072013-174520/.
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A indústria brasileira de fertilizantes encontra-se submetida a um sistema de tributação que pode anular a concorrência do produto nacional em relação ao importado, em função da configuração geográfica da oferta doméstica e do fato do produto importado desfrutar de benefícios tarifários. Tais benéficos são justificados pela grande dependência que a agricultura brasileira tem deste importante insumo e, a localização do consumidor em relação aos principais portos de entrada do produto e da indústria nacional é uma informação estratégica para o mercado e para a viabilidade de projetos de investimentos domésticos. O presente estudo analisou os custos logísticos que incidem sobre os principais fertilizantes importados através da utilização de uma nova metodologia: o uso de um modelo digital de terreno. O modelo foi gerado interpolando-se indicadores de preços construídos a partir das variáveis que atuam na formação dos preços dos fertilizantes importados por meio de três métodos diferentes. O produto do estudo é um modelo digital que descreve o comportamento do preço do fertilizante importado de uma forma contínua sobre a superfície. Este modelo foi usado para analisar a área de abrangência do fertilizante importado de cada um dos principais portos e elaborar simulações a partir da manipulação das variáveis do modelo.The Brazilian fertilizer industry is subject to a tax system that can cancel the competition of the national product with regard to imported, depending on the geographic configuration of the domestic supply and the fact that the imported products take advantage of tariff benefits. Such benefits are justified by the large dependence of the Brazilian agriculture has this important input. Therefore, the location of the consumer market in relation to the main ports of entry of the input and the domestic industry is a strategic information to the market and the viability of domestic investment projects. This study analyzed the logistics costs imposed on the main imported fertilizers by using a new methodology: the use of a digital terrain model. The model was generated interpolating price indicators constructed from the variables that act in the formation of prices of imported fertilizers by three different methods. The product of the study is a digital model that describes the behavior of the imported fertilizer price in a continuous manner over the surface. This model was used to analyze the coverage area of the imported fertilizer for each of the main ports and prepare simulations from the manipulation of model variables.
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Berveglieri, Adilson [UNESP]. "Classificação fuzzy de vertentes por krigagem e TPS com agregação de regiões via diagrama de Voronoi." Universidade Estadual Paulista (UNESP), 2011. http://hdl.handle.net/11449/88156.
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As vertentes, como superf cies inclinadas, consistem em express~oes da Geomorfologia moldadas por fatores naturais (end ogenos e ex ogenos) e pelo pr oprio homem. Suas formas determinam o uxo ou o ac umulo de agua e representam caracter sticas fundamentais para a preven c~ao e resolu c~ao de problemas associados ao relevo, tais como utiliza c~ao do solo, constru c~ao civil entre outros. A classi ca c~ao da vertente em c oncava, convexa ou retil - nea permite a identi ca c~ao de areas conforme sua declividade. Assim, por meio de uma grade retangular regular, base do modelo digital de terreno, gera-se uma malha interpolada por fun c~oes estimadoras: thin-plate spline, que possui caracter sticas de suaviza c~ao e krigagem, que al em da suavidade tamb em considera a depend encia espacial. Logo ap os, a classi ca c~ao e feita, obedecendo a infer encia fuzzy baseada em fun c~oes de pertin encia que de nem classes a partir do c alculo da inclina c~ao e da concavidade ou convexidade do terreno. Entretanto, o resultado dessa classi ca c~ao est a atrelado a resolu c~ao da malha, n~ao permitindo fazer qualquer corre c~ao pontual. Pois, pequenas areas de pouca signi c ancia podem ser formadas, necessitando elimin a-las. Nesse sentido, para que o resultado seja ajustado, aplica-se o diagrama de Voronoi, caracterizado por sua rela c~ao de abrang encia e proximidade, como ferramenta para agregar regi~oes anteriormente classi cadas de modo a permitir um ajuste local e tornar o resultado mais condizente com a area em estudo, quando comparada a mapas geomorfol ogicos correspondentes
Slopes, such as inclined surfaces, consist in geomorphological expressions shaped by natural factors (endogenous and exogenous) and also by man himself. Their shapes determine the ow or accumulation of water and represent fundamental characteristics for the prevention and resolution of problems associated with relief, as land use, buildings, and others. Classi- cating slopes in concave, convex or straight allows to identi cate areas based on declivity. Thus, by regular rectangular grid which represents a digital terrain model, it generates a interpolated mesh by estimator functions: thin-plate spline, which has characteristics of smoothing, and kriging, which besides smoothing also considers spatial dependence. After that, the classi cation is realized according to fuzzy inference based on membership functions that de ne classes from the calculation of the slope and concavity or convexity of the ground. However, the classi cation depends on mesh resolution and it not allows any point correction. Once small areas with little importance can be formed requiring eliminate them. In order to adjust the result, it applies the Voronoi diagram, characterized by its comprisement and close relationship and scope, as a tool to aggregate regions previously classi ed and allow a local adjustment, that can provides a consistent result in study areas, if it was compared to the corresponding geomorphological maps
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Edlund, Susanne. "Framkomlighetsanalys med hjälp av en digital terrängmodell och kartdata." Thesis, Linköping University, Department of Computer and Information Science, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-2413.
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Driveability analysis of terrain data offers an important technique for decision support for all kinds of movements in the terrain. The work described in this report uses a high resolution digital terrain model generated from the laser radar data and further processed by the Category Viewer program, and information from the Real Estate Map. Properties of features found in a filtering process are calculated and compared with a set of rules in a knowledge base to get a driveability cost. This cost is then visualized in a graphical user interface.
An evaluation of what driveability is and what it is affected by is performed, and a general cost function is developed, which can be used even if not all relevant information is available.
The methods for property and cost calculation need to be developed further, as well as the rules in the knowledge base. However, the implemented program offers a good framework for furtherresearch in the area.
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Tyagur, Nataliya. "Zpřesnění digitálního modelu metodami laserového skenování." Doctoral thesis, Vysoké učení technické v Brně. Fakulta stavební, 2019. http://www.nusl.cz/ntk/nusl-408018.
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The doctoral thesis deals with mobile laser scanning and data processing. Mobile laser scanning was carried out in the Moravian Karst in Suchy zleb and Pusty zleb at various seasons. Further scanning was carried out at the Training Forest Enterprise Masaryk Forest Křtiny. The Riegl VMX-450 scanner was used to collect 3D data. The data files were processed in the OPALS software. For the extraction of ground and non-ground points from the laser cloud, a combination of hierarchical interpolation and robust filtering was used. Subsequently, the terrain points were used to model digital terrain models with grids 0.05 x 0.05 m, 0.25 x 0.25 m, 1 x 1 m. Furthermore, digital models from Moravian Karst were compared with the Digital relief model of the Czech Republic 4G and reference points. Digital models from Masaryk Forest Křtiny were compared with photogrammetric and terrestrial data. The high accuracy of the derived DTMs is about 0.10 m. The high quality of the derived DTM can be used to monitor and analyze field changes and morphological structures.
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Sardeiro, Simone Soraia Silva. "Modelagem digital de terreno do município de Graccho Cardoso, nordeste de Sergipe." Universidade Federal de Sergipe, 2016. https://ri.ufs.br/handle/riufs/5412.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPESIn the Geographic Information Systems platform, Digital Terrain Model (DTM) is a mathematical way, to show a natural feature that occurs in the Earth's surface. The purpose of this dissertation was to build a digital terrain model for the municipality of Graccho Cardoso, approximate scale 1:65.000, and analyze their products (contour map, slope map, shading map, and geological and geomorphological maps superimposed on the digital terrain model). The city of Graccho Cardoso is located in the north of the state of Sergipe, at about 120 km away from Aracaju. The study area was selected to present geomorphological and geological diversity and have Satellite Images (SRTM) with good resolution for the selected working range. Graccho Cardoso occurs in quotas ranging between 140 m and 280 m above sea level, where the predominant pattern dendritic drainage. Since its relief is under the process planing and pediplanation. Its steepness varies from 0% to over 75%. Where there is a predominance with the angle of inclination between 3 and 45%. It has been more remarkable shading which fit fluvial channels, showing that the notching index or grain dissection is more pronounced. It has two types of morphostructures: Remnants Fold Roots (Sergipano Orogenic System – Proterozoic) and Sedimentary Basins and Covers (Superficial Formations – Fanerozoic). The results obtained by integration of the various maps shows up very similar to many traditional data mapping surveys.
No ambiente dos Sistemas de Informações Geográficas, o Modelo Digital de Terreno (MDT) representa, de maneira matemática, uma feição natural que ocorre na superfície terrestre. A proposta dessa dissertação foi confeccionar um modelo digital de terreno para o município de Graccho Cardoso, na escala aproximada de 1:65.000, e analisar os seus produtos (mapa de curva de nível, mapa de declividade, modelo sombreado, mapa geomorfológico e mapa geológico sobrepostos ao modelo digital de terreno). O município de Graccho Cardoso está localizado na região norte do Estado de Sergipe, a cerca de 120 km de distância de Aracaju. A área de estudo foi selecionada por apresentar diversidade geomorfológica e geológica e, dispor de Imagens de Satélite (SRTM) com boa resolução para a escala de trabalho escolhida. A região de Graccho Cardoso ocorre em cotas variando entre de 140 m e 280 m de altitude, onde predomina o padrão de drenagem dendrítico. O seu relevo está sob o processo de aplainamento e pediplanação. Sua declividade varia entre 0 % a mais de 75 %. Onde existe um predomínio ondulado, o ângulo de inclinação varia entre 3 a 45%. Tem-se um sombreado mais marcante onde se encaixam os canais fluviais, mostrando que o índice de entalhamento, ou grau de dissecação, é mais acentuado. Possui dois tipos de morfoestruturas: Remanescentes de Raízes de Dobramentos (Sistema Orogênico Sergipano do Proterozóico) e, Bacias e Coberturas Sedimentares (Formações Superficiais do Fanerozóico). Os resultados obtidos pela integração dos diversos mapas mostram-se muitos similares com os dados tradicionais de levantamentos cartográficos.
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Fernandez, Paulo Alexandre Justo. "Avaliação do risco de inundação em zonas urbanas com a integração de dados LIDAR e cartografia a escala grande." Doctoral thesis, Universidade de Évora, 2015. http://hdl.handle.net/10174/18221.
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As inundações são um dos desastres naturais com mais impacto, provocando mortes, afectando pessoas e causando perdas económicas elevadas tendo a sua frequência aumentado nos últimos anos. A avaliação do risco de inundação apresenta um carácter multidisciplinar, e a abordagem deve ser centrada no perigo e na vulnerabilidade. O objectivo deste estudo é desenvolver uma metodologia para avaliação do risco de inundação em zonas urbanas, tendo como base a melhoria da modelação digital da superfície de escoamento, e da estimativa da vulnerabilidade à inundação. No âmbito da modelação hidráulica de inundações, foi desenvolvido, testado e validado um método para a criação de um Modelo Digital de Superfície de escoamento (MDSe) com exactidão e resolução espacial elevadas, pela integração de informação geográfica existente e obtida de diferentes fontes. Os resultados das simulações do modelo LISFLOOD-FP mostram que a integração de dados LiDAR e cartografia a escala grande na construção do MDSe possibilitou um bom ajustamento do modelo no cálculo da altura de água no leito do rio e da extensão de inundação. Contudo, a integração de dados de vegetação, provenientes de imagens aéreas ortoretificadas CIR de alta resolução, contribuiu, ainda, para uma melhoria desse desempenho do modelo. A vulnerabilidade é um conceito multi-dimensional e complexo, cuja medição e classificação apresentam uma elevada incerteza. Neste trabalho foram utilizadas duas abordagens para modelação da vulnerabilidade à inundação, através da Análise Multicritério Espacial e da Análise de Componentes Principais. Os resultados demonstram que o método de agregação e a escala de análise influenciam a classificação da vulnerabilidade à inundação. É importante a estimativa da vulnerabilidade à escala local (subsecção estatística) para fornecer informação detalhada para a avaliação do risco de inundações em zonas urbanas: ABSTRACT: Floods are one of the natural disasters with more impact, that cause deaths, affect people and bring high economic damage. Their frequency has increased in recent years. The flood risk assessment is multidisciplinary, and its modelling should be focused on hazard and vulnerability. The objective of this work is to develop a urban flood risk assessment methodology based on improvements of digital surface flow modelling and flood vulnerability prediction. In the scope of the hydraulic flood modelling was developed, tested, and validated a methodology to create a Digital Surface Flow Model (DSMf) with high accuracy and resolution by integrating geographic information from various data sources. The LISFLOOD-FP model runs show that the integration of LiDAR data and large scale cartography to create a DSMf allows a good model fit to water levels and flood extension prediction. However, the addiction of vegetation information, extracted from colour infrared ortoretified images (CIR) of high spatial resolution, contributed to improving of the model performance. The vulnerability is a multi-dimensional and complex concept, measured and classified with high uncertainty. In this study, it was used two flood vulnerability modelling approaches through Spatial Multicriteria Analysis and Principal Component Analysis. The results demonstrate that the aggregation method and the scale of the analysis affect the flood vulnerability rating. It is important to estimate the vulnerability at local-scale (neighbourhoods) to provide detailed information for urban flood risk assessment.
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Rodrigues, Avilmar Antonio. "Uso de veículos aéreos não tripulados para mapeamento e avaliação de erosão urbana." Universidade Federal de Goiás, 2016. http://repositorio.bc.ufg.br/tede/handle/tede/6646.
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This research aimed to evaluate the use of Unmanned Aerial Vehicle (UAV) as a platform for taking aerial photographs for mapping erosion planialtimetric located in urban areas. In addition, we evaluated the need to use or not to field control points for the generation of Digital Surface Model (DSM) and ortomosaico as tools to evaluate the erosive process. Despite the wide variation in attitude of aerial photographs that make up the aerophotogrammetric block arising from the instability of the UAV, it was possible to generate the MDS and ortomosaico with or without control points. This research was conducted in two urban erosions located in Goiania in Sector Fonte Nova in the stream of grass and the other in Silvânia called foot-washing. Whole generation of MDS, Digital Surface Model (MDT) and ortomosaico were performed in Agisoft PhotoScan program in semi-automatic processing, if used control points, or automatic without control points. The ortomosaicos generated without control points presented rotation, translation and scale of different generated with support. In addition, MDS generated without control points showed elevation or lowering of the reference surface with respect to the generated control, it is emphasized that these discrepancies are not constant. When performing automatic conversion of MDS to MDT, it was realized that the program was not able to eliminate the shrub vegetation located within the erosion. The vegetation or tree, shrub or undergrowth (grass) prevents proper limitation of erosion to the volume calculation. But unlike the MDS generated between two distinct epochs identifies the changes in the interval of time in areas without vegetation. The use of control points was essential to ensure the orientation, scale and the reference plane in the products generated from aerial photographs and thus evaluate the changes. Anyway, the UAV can be used as a platform for taking aerial photographs for generating cartographic products that enable the mapping and evaluation of erosions.
Esta pesquisa teve por objetivo avaliar a utilização do Veículo Aéreo Não Tripulado (VANT) como plataforma para a tomada de fotografias aéreas para o mapeamento planialtimétrico de erosão situada em zona urbana. Além disso, analisou-se a necessidade de utilização ou não de pontos de controle de campo para a geração de Modelo Digital de Superfície (MDS) e ortomosaico como instrumentos para examinar o processo erosivo. Apesar da grande variação da atitude da aeronave durante a obtenção das fotografias aéreas que compõem o bloco aerofotogramétrico, foi possível gerar o MDS e o ortomosaico com ou sem pontos de controle. Este estudo foi realizado em duas erosões urbanas, uma situada em Goiânia-GO, no Setor Fonte Nova/Córrego do Capim, e a outra em Silvânia-GO, denominada de Lava-Pés. Toda a geração dos MDS, Modelo Digital de Terreno (MDT) e ortomosaico foram realizados no programa Agisoft PhotoScan, em processamento semiautomático (i.e., com pontos de controle) e automático (i.e., sem pontos de controle). Os ortomosaicos gerados sem pontos de controle apresentaram rotação, translação e escala diferente dos gerados com apoio. Ademais, os MDS gerados sem pontos de controle apresentaram elevação ou rebaixamento da superfície de referência em relação aos gerados com controle. Ressalta-se, ainda, que essas discrepâncias não foram constantes. Ao realizar a conversão automática do MDS para o MDT, percebeu-se que o programa não foi capaz de eliminar a vegetação arbustiva localizada no interior da erosão. As vegetações arbórea, arbustiva ou rasteira (gramíneas) impedem a correta delimitação da erosão para o cálculo do volume. Porém, a diferença dos MDS gerados entre duas épocas distintas propicia identificar as alterações ocorridas nesse intervalo de tempo nas regiões sem cobertura vegetal. O uso de pontos de controle foi essencial para garantir a orientação, a escala e o plano de referência nos produtos gerados a partir das fotografias aéreas e, assim, avaliar as modificações da erosão. Por fim, o VANT pode ser utilizado como plataforma para a tomada de fotografias aéreas para gerar produtos cartográficos que possibilitem o mapeamento e as avaliações das erosões, sobretudo em áreas urbanas.
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Coelho, Fabrício Fernandes. "Comparação de métodos de mapeamento digital de solos através de variáveis geomorfométricas e sistemas de informações geográficas." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2010. http://hdl.handle.net/10183/25062.
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Mapas pedológicos são fontes de informações primordiais para planejamento e manejo de uso do solo, porém apresentam altos custos de produção. A fim de produzir mapas de solos a partir de mapas existentes, o presente trabalho objetiva testar e comparar métodos de classificação em estágio único (regressões logísticas múltiplas multinomiais e Bayes) e em estágios múltiplos (CART, J48 e LMT) com utilização de sistemas de informações geográficas e de variáveis geomorfométricas para produção de mapas pedológicos com legenda original e simplificada. A base de dados foi gerenciada em ambiente ArcGis onde as variáveis e o mapa original foram relacionados através de amostras de treinamento para os algoritmos. O resultado dos algoritmos obtidos no software Weka foram implementados no ArcGis para a confecção dos mapas. Foram gerados matrizes de erros para análise de acurácias dos mapas. As variáveis geomorfométricas de declividade, perfil e plano de curvatura, elevação e índice de umidade topográfica são aquelas que melhor explicam a distribuição espacial das classes de solo. Os métodos de classificação em estágio múltiplo apresentaram sensíveis melhoras nas acurácias globais, porém significativas melhoras nos índices Kappa. A utilização de legenda simplificada aumentou significativamente as acurácias do produtor e do usuário, porém sensível melhora na acurácia global e índice Kappa.Soil maps are sources of important information for land planning and management, but are expensive to produce. This study proposes testing and comparing single stage classification methods (multiple multinomial logistic regression and Bayes) and multiple stage classification methods (CART, J48 and LMT) using geographic information system and terrain parameters for producing soil maps with both original and simplified legend. In ArcGis environment terrain parameters and original soil map were sampled for training algoritms. The results from statistical software Weka were implemented in ArcGis environment to generate digital soil maps. Error matrices were genereted for analysis accuracies of the maps.The terrain parameters that best explained soil distribution were slope, profile and planar curvature, elevation, and topographic wetness index. The multiple stage classification methods showed small improvements in overall accuracies and large improvements in the Kappa index. Simplification of the original legend significantly increased the producer and user accuracies, however produced small improvements in overall accuracies and Kappa index.
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Castenvall, Anna, and Elin Petersson. "Utvärdering av två digitala terrängmodeller på öppna ytor : Framställda med NRTK-GNSS och Laserdata NH." Thesis, Högskolan i Gävle, Samhällsbyggnad, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-32663.
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En digital terrängmodell (DTM) representerar endast markytans form och har en bred användning inom t.ex. samhällsplanering. Det finns olika framställningsmetoder för att skapa en DTM, där de mest använda metoderna är mark- eller flygburen laserskanning samt terrester- eller satellitbaserad mätning. Flygburen laserskanning (FLS) använder sig av tekniken LiDAR (Light Detection And Ranging) där avstånd mäts med laser. Lantmäteriet påbörjade ett projekt 2009, vilket gick ut på att laserskanna hela Sverige med FLS och projektet blev klart 2019. Resultatet blev Laserdata NH (Nationella Höjdmodellen) med en lägesnoggrannhet i höjd på 0,1 m. Syftet med studien är att kontrollera mätosäkerheten för Laserdata NH samt undersöka om den kan ersätta terrestra mätningar, t.ex. GNSS vid skapande av DTM:er. Studieområdet är ca 0,85 ha och består av en gräsyta omgiven av grusvägar. Området är beläget i Teknikparken, Gävle. För att se ifall Laserdata NH kan ersätta GNSS-mätningar skapades en DTM från Laserdata NH samt en DTM från mätningar med NRTK-GNSS. Alla inmätningar följde de krav och toleranser vilka specificeras i SIS-TS 21144:2016. För att kunna kontrollera mätosäkerheten för Laserdata NH mättes kontrollprofiler in, vilka agerade som referens. Kontrollprofilerna användes även som referens när de båda DTM:erna jämfördes mot varandra. Max- och min avvikelse, medelavvikelse, standardosäkerhet samt RMS räknades ut på varje enskild profil, per markyta och för de två modellerna. Beräkningarna utfördes för att se ifall värdena låg för högt eller för lågt i någon del av ett område samt för att kunna se sannolikheten för systematiska avvikelser. En statistisk analys utfördes för att se ifall det finns någon skillnad mellan DTM och kontrollprofilernas medelavvikelse. Resultatet visade att det fanns en statistisk signifikant avvikelse på medelavvikelsen mellan DTM skapad av Laserdata NH och kontrollprofiler för både grus- och gräsytorna. Detta innebär att Laserdata NH inte kan ersätta NRTK-GNSS på öppna, jämna gräsytor eller plana grusytor. Kontrollerna av de två DTM:erna klarar toleranserna enligt SIS-TS 21144:2016 och anses vara tillförlitliga. Studien kom till slutsatsen att Laserdata NH kan användas utan komplettering till översiktliga planeringar. Detaljerade analyser med Laserdata NH behöver dock kompletteras med ytterligare mätningar eller ortofoto för att erhålla mer trovärdiga resultat.A Digital Terrain Model (DTM) only represent the surface and has a broad application within, for example, community planning. There are different ways of producing a DTM, with the most common methods being ground- or airborne laser scanning and terrestrial- or satellite based measurement. Airborne laser scanning (ALS) uses the technique LiDAR (Light Detection and Ranging) which measures distances with laser. Lantmäteriet, the Swedish cadastral mapping and surveying authority, began in 2009 with a project to scan entire Sweden with ALS and was finished in 2019. The outcome of the project was a new national height model that is called Laserdata NH with a positional accuracy of 0,1 m in height. The purpose of this bachelor thesis is to study the uncertainty of Laserdata NH and to investigate if it can replace terrestrial measurements, for example replacing Laserdata NH with GNSS mapping. The study area is approximately 0,85 hectares and consists of a grassland area surrounded by gravel paths. The area is located in Teknikparken, Gävle. To see if Laserdata NH can replace GNSS-measurements a DTM was created from Laserdata NH as well as a DTM created from measurements with NRTK-GNSS. All measurements followed the requirements and tolerances according to SIS-TS 21144:2016. To control the uncertainty for Laserdata NH, control profiles were measured, which acted as a reference. The control profiles were also used as a reference when comparing the two DTMs. Max and min deviation, mean deviation, standard deviation and RMS were calculated for each profile, per ground area and using two models. The calculations were performed to see if the values were too high or too low in any part of an area and to be able to see the probability of systematic deviations. A statistical analysis was performed to see if there were any difference between the DTM and the mean deviation of the control profiles. The result showed that there was a statistic significant deviation on the mean deviation between the DTM created by Laserdata NH and the control profile for both the gravel and the grass surface. This means that Laserdata NH cannot replace NRTK-GNSS on open, plain grass or gravel surfaces. The controls of the two DTMs are within the tolerances according to SIS-TS 21144:2016 and are considered reliable. The study concluded that Laserdata NH can be used without supplement to do general plans. However, for detailed analysis Laserdata NH needs to be supplemented with additional measurements or orthophoto.
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Klusák, Petr. "Tvorba digitálního modelu terénu zadané části lokality Jedovnice." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2014. http://www.nusl.cz/ntk/nusl-227081.
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The aim of my master’s thesis was to createa digital terrain model (DTM). The assigned data were to be processed, updated, unified and subsequently used to create a purpose map on the scale of 1:500. The selected area issituated near the village of Jedovnice; to be more specific, the area includes a meadow located along the Podomský rivulet and the adjacent forest. To create the purpose map, the MicroStation software was used (version V8). Furthermore, the Atlas DTM software (version 4)was used to create the digital terrain model, colour hypsometry and an exposure map and finally, the AutoCAD software (student version 2013) was used for visualizing and matching objects with textures.
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Gustafsson, Jacob. "Mapping drainage of the rootless shield volcano at Dimmuborgir, northern Iceland." Thesis, Stockholms universitet, Institutionen för geologiska vetenskaper, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-131405.
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Dimmuborgir is thought to be a former rootless shield volcano, which was fed with lava from a nearby crater row, 2170 ± 38 calendar years before present. In this study, the orientation of striations on the sides of lava channels, collapse structures and lava pillars were measured to find out how the enigmatic ~2 km by 2 km volcanic structure at Dimmuborgir was drained. During one week of field work 149 striations were found and measured, with respect to their dip angle, dip direction and elevation. Their locations were recorded with a GPS (Global Positioning System) receiver. The orientations of the striations were visualized on Google Earth satellite images and on images from a Digital Terrain Model (DTM) of Dimmuborgir. Resulting visualizations show that Dimmuborgir was drained radially and in multiple stages. It is concluded that Dimmuborgir was drained towards the west, the northeast and the southeast. The drainage towards the west was channeled. The drainage towards the northeast and the southeast was radially inwards, towards the collapsed parts of Dimmuborgir.
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Wang, Chen. "Large-scale 3D environmental modelling and visualisation for flood hazard warning." Thesis, University of Bradford, 2009. http://hdl.handle.net/10454/3350.
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3D environment reconstruction has received great interest in recent years in areas such as city planning, virtual tourism and flood hazard warning. With the rapid development of computer technologies, it has become possible and necessary to develop new methodologies and techniques for real time simulation for virtual environments applications. This thesis proposes a novel dynamic simulation scheme for flood hazard warning. The work consists of three main parts: digital terrain modelling; 3D environmental reconstruction and system development; flood simulation models. The digital terrain model is constructed using real world measurement data of GIS, in terms of digital elevation data and satellite image data. An NTSP algorithm is proposed for very large data assessing, terrain modelling and visualisation. A pyramidal data arrangement structure is used for dealing with the requirements of terrain details with different resolutions. The 3D environmental reconstruction system is made up of environmental image segmentation for object identification, a new shape match method and an intelligent reconstruction system. The active contours-based multi-resolution vector-valued framework and the multi-seed region growing method are both used for extracting necessary objects from images. The shape match method is used with a template in the spatial domain for a 3D detailed small scale urban environment reconstruction. The intelligent reconstruction system is designed to recreate the whole model based on specific features of objects for large scale environment reconstruction. This study then proposes a new flood simulation scheme which is an important application of the 3D environmental reconstruction system. Two new flooding models have been developed. The first one is flood spreading model which is useful for large scale flood simulation. It consists of flooding image spatial segmentation, a water level calculation process, a standard gradient descent method for energy minimization, a flood region search and a merge process. The finite volume hydrodynamic model is built from shallow water equations which is useful for urban area flood simulation. The proposed 3D urban environment reconstruction system was tested on our simulation platform. The experiment results indicate that this method is capable of dealing with complicated and high resolution region reconstruction which is useful for many applications. When testing the 3D flood simulation system, the simulation results are very close to the real flood situation, and this method has faster speed and greater accuracy of simulating the inundation area in comparison to the conventional flood simulation models
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Coelho, Alessandra Martins. "Aplicação da geocomputação a estudos de susceptibilidade de deslizamentos de terra." Universidade do Estado do Rio de Janeiro, 2012. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=6552.
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Esta tese propôs uma metodologia para detecção de áreas susceptíveis a deslizamentos
de terra a partir de imagens aéreas, culminando no desenvolvimento de uma ferramenta
computacional, denominada SASD/T, para testar a metodologia. Para justificar esta pesquisa,
um levantamento sobre os desastres naturais da história brasileira relacionada a deslizamentos
de terra e as metodologias utilizadas para a detecção e análise de áreas susceptíveis a
deslizamentos de terra foi realizado. Estudos preliminares de visualização 3D e conceitos
relacionados ao mapeamento 3D foram realizados. Estereoscopia foi implementada para
visualizar tridimensionalmente a região selecionada. As altitudes foram encontradas através
de paralaxe, a partir dos pontos homólogos encontrados pelo algoritmo SIFT. Os
experimentos foram realizados com imagens da cidade de Nova Friburgo. O experimento
inicial mostrou que o resultado obtido utilizando SIFT em conjunto com o filtro proposto, foi
bastante significativo ao ser comparado com os resultados de Fernandes (2008) e Carmo
(2010), devido ao número de pontos homólogos encontrados e da superfície gerada. Para
detectar os locais susceptíveis a deslizamentos, informações como altitude, declividade,
orientação e curvatura foram extraídas dos pares estéreos e, em conjunto com as variáveis
inseridas pelo usuário, forneceram uma análise de quão uma determinada área é susceptível a
deslizamentos. A metodologia proposta pode ser estendida para a avaliação e previsão de
riscos de deslizamento de terra de qualquer outra região, uma vez que permite a interação com
o usuário, de modo que este especifique as características, os itens e as ponderações
necessárias à análise em questão.The purpose of this thesis is a methodology to detect locations susceptible to landslides from the aerial images, culminating in the development of software, denominated SASD/T, to testing the methodology. To justify this research, a survey about natural disasters in Brazilian history related to landslides and methodologies used for detection and analysis of areas susceptible to landslides was realized. Preliminaries studies of the 3D visualization and concepts related to 3D mapping of an area were carried out. The stereoscopy technique was implemented to visualize three-dimensionally the selected region. Altitudes were found via parallax, from the homologous points found by the SIFT algorithm. The experiments were performed with Nova Friburgo city images. The initial experiment showed that the results obtained using the SIFT algorithm together with the proposed filter was highly significant when compared with the results of Fernandes (2008) and Carmo (2010), due to the number of homologous points found and the generated surface. To detect locations susceptible to landslides, information such as altitude, slope, aspect and curvature areas was extracted from the stereo pairs and, together with the variables entered by the user, was provided an analysis of how a particular area is susceptible to landslides. The proposed methodology can be extended to the evaluation and prediction of landslide risks in any other region, since it allows interaction with the user, so that it specifies the characteristics, the items and the weights needed for the analysis in question.
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Persson, Erik, and Fredric Sjöwall. "Utvärdering av metoder för framställning och kontroll av digitala terrängmodeller." Thesis, Högskolan i Gävle, Avdelningen för Industriell utveckling, IT och Samhällsbyggnad, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-11985.
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Today there are many applications of digital terrain models (DTM) and the requirements of low uncertainty increases. Most of the DTM are produced with Global Navigation Satellite System (GNSS), terrestrial laser scanning (TLS), airborne laser scanning (ALS) and total stations. Guidelines for the preparation and verification of DTM are found in Swedish Standards Institute – Technical Specifications (SIS-TS) 21144:2007 and SIS-TS 21145:2007. These were defined in collaboration between Swedish National Rail Administration, Banverket, and Swedish Road Administration, Vägverket, to satisfy the needs of requirement formulations in the production of DTM planning, design and construction. The purpose of this paper is to produce and control DTM over Åkermans kulle, located west of the University of Gävle, according to SIS TS 21144:2007 using GNSS with network-RTK, TLS and ALS. Control of these was then performed by profile surveying with total station in accordance with SIS-TS 21145:2007 and by comparing the models against each other. Based on these results the control methods were evaluated. The area is approximately 2 ha and consists of very rough grassland with some vegetation. The post processing of the data was done in software SBG Geo Professional School, Cyclone 7.3 and Microsoft Excel. The profile-based verification showed that GNSS gives the smallest deviation from reality for this type of area, with a mean deviation of 0.048 m, while the TLS and ALS deviated 0.162 m and 0.255 m. For the surface based control the largest deviation was between ALS and GNSS with an average deviation of 0.270 m and the smallest between ALS-TLS with an average deviation of 0.099 m. In the production of DTM aim, uncertainty requirements, area and type of terrain should be taken into account and carefully analyzed. Based on this analysis, the most suitable method should be selected. Profile measurement is the most suited method for control since it generates a veracious depiction of the reality. Our results show that for hilly vegetated areas GNSS are preferable while TLS and ALS are more suited to plane areas without vegetation. A single national standard for the production and control of the DTM should be developed as only technical specifications exist today.Användningsområden för digitala terrängmodeller (DTM) är idag många och kraven på låg osäkerhet ökar. DTM kan framställas med Global Navigation Satellite System (GNSS), terrester laserskanning (TLS), flygburen laserskanning (FLS) eller totalstation. Riktlinjer för framställning och kontroll av DTM finns i Swedish Standards Institute - Tekniska specifikationer (SIS-TS) 21144:2007 och SIS 21145:2007. Dessa framtogs i ett samarbete mellan Banverket och Vägverket, idag Trafikverket, för att tillfredsställa behoven av kravformuleringar vid framställning av DTM för planering, projektering och byggande. Syftet med detta examensarbete är att framställa DTM över Åkermans kulle, beläget väster om Högskolan i Gävle enligt SIS-TS 21144:2007. Detta med hjälp av GNSS med nätverks-RTK, TLS och FLS, samt kontroll genom profilinmätning med totalstation enligt SIS-TS 21145:2007 och ytbaserad kontroll av modellerna mot varandra. Utgående från dessa resultat utvärderades kontrollmetoderna. Området är ca 2 ha stort och består av mycket kuperad ängsmark med viss vegetation. Efterbearbetningen av inmätta data skedde i programvarorna SBG Geo Professional School 2012, Cyclone 7.3 samt Microsoft Excel. Den profilbaserade kontrollen visade att GNSS är den metod som ger lägst osäkerhet för denna typ av område, med en medelavvikelse på 0,048 m, medan TLS och FLS avvek 0,162 m respektive 0,255 m. För den ytbaserade kontrollen var de största avvikelserna mellan FLS och GNSS, med en medelavvikelse på 0,270 m och den lägsta medelavvikelsen på 0,099 m mellan FLS och TLS. Vid framställning av terrängmodeller bör syfte, osäkerhetskrav, areal och typ av terräng tas i beaktande och analyseras noggrant. Utifrån denna analys bör den mest sanningsenliga metoden väljas. För kontroll är profilmätning med totalstation mest lämpat då det ger en sanningsenlig bild av verkligheten. Våra resultat visar att för kuperade vegetationsrika områden är GNSS att föredra medan TLS och FLS passar bättre för plana områden utan vegetation. En gemensam nationell standard för framställning och kontroll av DTM bör tas fram då det i dagsläget endast finns specifikationer.
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Panchártek, Jan. "Podklady pro tvorbu mapy pro orientační běh." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2013. http://www.nusl.cz/ntk/nusl-226211.
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This thesis is about using airborne laser scanning data for making maps for Orienteering. In this thesis were used altimetry data DMR 4G and DMR 5G. These data are provided by ČUZK. The control measuring was made in choosen area to verify the accuracy. In this thesis is described procedure of data collection and their treatment. The results of this thesis are two illustrations of the orienteering maps.
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Eskina, Ksenija, and Ali Watoot. "En jämförelsestudie mellan punktmoln framställda med UAS-fotogrammetri och Laserdata NH på ett industriområde i Västsverige." Thesis, Högskolan Väst, Avdelningen för Matematik, Data- och Lantmäteriteknik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:hv:diva-15321.
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Framställning av digitala terrängmodell (Digital Terrain Model, DTM) är en viktig del för projekteringsunderlag vid markrelaterade frågor. Grunden för en DTM är punktmolnet som innehåller grunddata från mätningen. DTM är användbara i många olika områden, kvalitén bestäms beroende på vilken uppdrag som DTM gäller för. UAS-fotogrammetri är en av metoder som tillämpas för att framställa en DTM, det går även att framställa en DTM utifrån punktmoln från Laserdata NH. En DTM är en modell av endast markyta, där data samlas genom mätning av ett visst objekt. Syftet med detta examensarbete som är utfört vid Institutionen för ingenjörsvetenskap vid Högskolan Väst var att jämföra två olika metoder för framställning av ett punktmoln som är till underlag för en DTM. Punktmoln som framställs med egna mätningar från UASfotogrammetri och ett färdigt punktmoln från Laserdata NH. Målet med jämförelsen är att undersöka om det går att ersätta UAS-fotogrammetri med den kostnadseffektiva Laserdata NH i projektet för ett industriområde (Lödöse varvet) i Lilla Edets kommun, samt om det går att ersätta den överlag. Med hjälp av Agisoft Metashape programvaran framställdes det punktmolnet från mätning från UAS av modellen DJI Phantom 4 Advanced, sedan jämfördes den mot det färdiga punktmolnet från Laserdata NH i CloudCompare programmet. Resultatet på denna studie visar att det går att ersätta UAS-fotogrammetri mot Laserdata NH i just denna och andra liknande projekt som har samma syfte och viss bestämd noggrannhet då punktmolnen inte avviker signifikant från varandra. Medan det inte går att ersätta de mot varandra överlag, då UAS-fotogrammetri erhåller högre noggrannhet när det gäller framställning av ett punktmoln jämfört med vad Laserdata NH har för noggrannhet på sina mätningarGeneration of Digital Terrain Model (DTM) is an essential part in project planning in questions related to spatial planning. Basis for the DTM is the point cloud which obtains initial data from the measurement. DTM can be used in different areas, accepted quality level is depending on the assignment for which DTM is produced. UAS-photogrammetry is one of the methods which is used for DTM generation, but it is possible to produce DTM from point cloud originated from Laserdata NH. A DTM is a model representing entirely terrain surface, where the data used for its generation gathers from measuring of a certain object. The purpose of this study accomplished at Department of Engineering Science at University West was to compare two different methods for point cloud generation as a basis for DTM. First point cloud generated comes from own measurement with UAS-photogrammetry and second is a point cloud from acquired Laserdata NH. The goal of the comparison is to examine if it is possible to replace UAS-photogrammetry with the cost effective Laserdata NH in the project for the industrial area (Lödöse varvet) in Lilla Edet municipality, and if it is possible to replace it generally. With help of Agisoft Metashape software the point cloud from UAS-measurement with DJI Phantom 4 Advanced was generated and then compared to Laserdata NH point cloud in CloudCompare program. Result of this study is showing that it is possible to replace UAS-photogrammetry with Laserdata NH in this specific and others similar projects which have same purpose and certain decided precision since point clouds are not significantly deviating from each other. While it is not possible to replace them generally, as UAS-photogrammetry obtains higher precision concerning point cloud generation compared to accuracy that Laserdata NH has in its measurements.
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Žilinskas, Linas. "Nuotolinių tyrimų metodais gautų duomenų patikimumo įvertinimas." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2013. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2013~D_20130621_143214-53614.
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Geografinei informacijai apie erdvinį žemės paviršių kaupti pastaruoju metu vis dažniau naudojamas vietovės skenavimo lazeriu iš orlaivio metodas LIDAR (Light Detection and Ranging). Šiuo metodu gaunama nereguliari taškinė labai tanki trijų dimensijų žemės paviršiaus objektų išsidėstymą sumodeliuojanti geometrinė ir radiometrinė informacija. Tai gana neseniai atsiradęs būdas, naudojamas žemės topografijos duomenims užrašyti, kuris Lietuvoje dar tik pradedamas naudoti. Dėl to naudinga ištirti šio metodo patikimumą, palyginant su įprastais duomenų surinkimo metodais (GPS), ir įvertinti šio metodo panaudojimo galimybes. Darbe nagrinėjama nuotolinių tyrimų metodais (LIDAR) gautų duomenų patikimumo problema. Tyrimo tikslas – nustatyti įvairiais metodais gautų reljefo aukščių duomenų patikimumą, analizuojant Riešės upelio baseino reljefą. Tyrimo eigoje buvo surinkti įvairiais metodais gauti Riešės upelio baseino reljefo duomenys; atlikti natūriniai matavimai pasirinktuose kontroliniuose ploteliuose, naudojantis geodeziniais instrumentais; pagal nuotolinių tyrimų gautus rezultatus sudarytas skaitmeninis reljefo modelis ir įvertintas jų tikslumas. Darbe palyginus natūrinių matavimų ir nuotolinių tyrimų metodais gautus rezultatus įrodyta, jog nuotoliniais tyrimų metodais gauti duomenys yra patikimi ir juos galima naudoti baseino tūriui ir plotui skaičiuoti.LIDAR terrain laser scanning technique is increasingly used in digital terrain model creation. This method provides dense uneven three-dimensional scatter geometric and radiometric information that simulates objects on earth’s surface. This is a relatively recent method used to record topographic data of the land. One of the key issues still associated with remote sensing methods is its reliability, which is why it is relevant to analyze and evaluate this aspect. This thesis aims at evaluating LIDAR data reliability, comparing them with data obtained by field measurements carried out at selected control areas using geodesic instruments. Riešės river basin area was selected as an object for the study and its elevation data have been investigated in the research. It was concluded that LIDAR data are reliable and can be used for the basin volume calculation. However, the size of the grid should be selected according to terrain relief.
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Cui, Zheng. "A Generalized Adaptive Mathematical Morphological Filter for LIDAR Data." FIU Digital Commons, 2013. http://digitalcommons.fiu.edu/etd/995.
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Airborne Light Detection and Ranging (LIDAR) technology has become the primary method to derive high-resolution Digital Terrain Models (DTMs), which are essential for studying Earth’s surface processes, such as flooding and landslides. The critical step in generating a DTM is to separate ground and non-ground measurements in a voluminous point LIDAR dataset, using a filter, because the DTM is created by interpolating ground points. As one of widely used filtering methods, the progressive morphological (PM) filter has the advantages of classifying the LIDAR data at the point level, a linear computational complexity, and preserving the geometric shapes of terrain features. The filter works well in an urban setting with a gentle slope and a mixture of vegetation and buildings. However, the PM filter often removes ground measurements incorrectly at the topographic high area, along with large sizes of non-ground objects, because it uses a constant threshold slope, resulting in “cut-off” errors. A novel cluster analysis method was developed in this study and incorporated into the PM filter to prevent the removal of the ground measurements at topographic highs.
Furthermore, to obtain the optimal filtering results for an area with undulating terrain, a trend analysis method was developed to adaptively estimate the slope-related thresholds of the PM filter based on changes of topographic slopes and the characteristics of non-terrain objects. The comparison of the PM and generalized adaptive PM (GAPM) filters for selected study areas indicates that the GAPM filter preserves the most “cut-off” points removed incorrectly by the PM filter. The application of the GAPM filter to seven ISPRS benchmark datasets shows that the GAPM filter reduces the filtering error by 20% on average, compared with the method used by the popular commercial software TerraScan. The combination of the cluster method, adaptive trend analysis, and the PM filter allows users without much experience in processing LIDAR data to effectively and efficiently identify ground measurements for the complex terrains in a large LIDAR data set. The GAPM filter is highly automatic and requires little human input. Therefore, it can significantly reduce the effort of manually processing voluminous LIDAR measurements.
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Gustafsson, Amanda, and Olov Wängborg. "Mätosäkerhet vid digital terrängmodellering med handhållen laserskanner : Undersökning av den handhållna laserskannern ZEB-REVO." Thesis, Högskolan i Gävle, Samhällsbyggnad, GIS, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-26841.
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En digital terrängmodell (DTM) är en representation av enbart själva markytan. Det finns flera metoder för att framställa DTM:er, där laserskanning har blivit en alltmer vanlig metod. Inom laserskanning är flygburen laserskanning (FLS) en flitigt använd metod, då metoden har fördelen av att kunna täcka stora områden på kort tid. Det finns dock nackdelar med FLS då datainsamlingen kan bli bristfällig i t.ex. skogsområden, där laserstrålar inte kan tränga igenom tät vegetation. Här kan handhållen laserskanning (HLS) vara ett bra alternativ då HLS går snabbt och inte behöver samma omfattande planering. Tidigare studier visar att HLS har många fördelar, men som dock inte kan hålla samma låga osäkerhet som terrester laserskanning (TLS). Det saknas däremot studier om hur HLS ställer sig mot mätningar med FLS. Syftet med studien är därför att utvärdera möjligheten att använda och tillämpa mätningar med HLS för framställning av DTM i skogsterräng gentemot FLS. Detta görs genom att jämföra respektive DTM:s lägesosäkerhet. I studien användes instrumentet ZEB-REVO för insamlingen av data för metoden HLS. Medan för FLS användes laserdata från Lantmäteriet. Från insamlad laserdata skapades därefter DTM:er. Dessa jämfördes mot ett antal kontrollprofiler som mättes in med totalstation. För respektive metod, HLS och FLS, beräknades medelvärde för höjdavvikelserna mot kontrollprofilerna där även standardavvikelse beräknades. Resultatet visar att DTM:en skapad av data från FLS beräknades ha en höjdavvikelse för hela området på 0,055 m som medelvärde gentemot inmätta kontrollprofiler. Standardavvikelsen för denna höjdavvikelse beräknades till 0,046 m för FLS. För DTM:en med data från HLS beräknades en höjdavvikelse på 0,043 m i medelvärde som bäst, där standardavvikelse beräknades till 0,034 m. Studien visar att metoderna HLS och FLS gav likvärdiga resultat gentemot de inmätta kontrollprofilerna, dock gav HLS generellt mindre standardavvikelse i jämförelse mot FLS. Vidare ansågs ZEB-REVO och dess tillhörande databearbetningsprogram GeoSLAM vara väldigt användarvänligt, där själva skanningen med instrumentet tog endast 10 minuter för studiens område på ca 2000 m2. Utifrån studiens resultat drogs slutsatsen att mätningar med HLS kan ge en likvärdig DTM, sett till osäkerheten, som FLS-mätningar. HLS kan därmed vara en kompletterande metod men att FLS är en fortsatt effektiv metod.A digital terrain model (DTM) represent exclusively the earth surface. There are several methods which can be utilized to create DTMs, where laser scanning have become a common used method. Airborne laser scanning (ALS) is often used since the method can cover a large area in a relatively short time. However a disadvantage with ALS is that the data collection, for a wooded area, can be inadequate due to penetration difficulties for some laser beams. For that reason a handheld laser scanner (HLS) can be an alternative since measurements can be done fast and does not need the same extensive planning. Earlier studies mention HLS to have several advantages but can still not yet be compared with terrestrial laser scanning (TLS) concerning the measurements uncertainty. There are, however, no studies that investigates how measurements with HLS stands against FLS. The purpose with the study is to evaluate the ability to use measurements from HLS to create a DTM for a wooded area in comparison with ALS. This is done by comparing the different uncertainties for each DTM. In the study the acquisition of HLS laser data was collected with the instrument ZEB-REVO and the ALS laser data was received from Lantmäteriet (cadastral mapping and surveying authority in Sweden). After the data acquisition a DTM were created from each data set (method). The DTMs were then compared to control profiles, which have been measured with total station. From the comparison with the control profiles average height deviation and standard deviation were calculated for each DTM. The result shows that the DTM created from ALS data received an average height deviation of 0,055 m for the whole area with a standard deviation of 0,046 m. Corresponding result for the DTM created from HLS data were calculated, at best, to 0,043 m in average height deviation and 0,034 m in standard deviation. The study shows that the methods HLS and ALS gave equivalent result regarding the comparison with the control profiles, however HLS gave a generally lower value for standard deviation. Furthermore ZEB-REVO with its processing program GeoSLAM was considered to be very easy and user friendly. The area (approx. 2000 m2) for the study was scanned within only 10 min. The conclusion which were drawn from the obtained result was that measurements with HLS can generate an equivalent DTM, concerning the uncertainty, as measurements with FLS. Thereby HLS can be a complementing method but still FLS is seen as an effective method.
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Bárta, František. "Zaměření a tvorba 3D modelu pro hydrotechnický projekt." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2013. http://www.nusl.cz/ntk/nusl-226225.
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The thesis deals with the issues of digital terrain model creation. It aims to explain the solution of an international contract, starting from gathering the data and finishing with the creation and visualization of the digital terrain model of the given location. The software AutoCAD Civil 3D 2013 is used for modeling. Main outcomes of the thesis are volume calculation of flood line, contoured map of the dam area, the digital model and its visualization.
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Nghiem, Huu-Luyen. "Evaluation des dommages induits par des mouvements de terrain sur des structures en maçonnerie à l'aide de la modélisation physique." Thesis, Université Grenoble Alpes (ComUE), 2015. http://www.theses.fr/2015GREAI012/document.
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Les structures en maçonnerie représentent une proportion importante des maisons individuelles et sont plus vulnérables notamment lorsqu'elles sont soumises à des mouvements de terrain. Pour faire face aux conséquences de ce problème, une plate-forme d'essais a été développée pour simuler des mouvements de terrain et leur effet sur des modèles de structure en surface. Ce travail de thèse s'appuie sur un modèle physique réduit et développe des méthodes d'évaluation des dommages des structures maçonnées à l'aide de l'expérimentation physique. Dans un premier temps, un modèle physique à échelle réduite sous gravité terrestre (1g) a été conçu pour reproduire ce phénomène. Ce modèle d'interaction sol-fondation-maçonnerie est à l'échelle de 1/40. Le sol analogique est constitué d'un sable de Fontainebleau. La fondation de la structure est fabriquée à partir de silicone liquide, et les murs en maçonnerie sont constitués de petits blocs en bois. Pour mesurer les champs de déplacement du sol et de la structure, une technique de corrélation d'images numériques (DIC) est utilisée. Des discussions à propos de l'usage de cette technique lors de la réalisation d'un essai, notamment la prise en compte des erreurs de mesures, ont été également abordées. Dans un deuxième temps, on évalue les dommages par les méthodes conventionnelles basées sur des indicateurs de dommages et des abaques. Ensuite, des nouveaux outils basés sur la technique DIC sont proposés pour réaliser une évaluation de dommages plus efficace, et plus aisée. Le premier outil se basant sur le modèle d'interaction sol-structure de Winkler permet d'identifier les modes de rupture dans la structure. Pour cela, le problème inverse de l'interaction sol-structure a été résolu et les modes de rupture du mur, basés sur les efforts internes, ont été identifiés. Ensuite, un modèle DIC-M est proposé pour reproduire les fissures dans la maçonnerie. Le point clé de ce modèle concerne les mouvements des blocs qui sont simulés par un système d'éléments distincts. Par ce moyen, la reproduction des fissures, puis l'identification et la quantification des fissures deviennent aisées. Plus précisément, un nouvel indicateur de dommages lié à la longueur des fissures permet de mieux quantifier les dommages et de cartographier les fissures. L'incertitude de mesure est déterminée par une simulation de Monte-Carlo des erreurs de déplacements. Dans un troisième temps, la performance des outils développés est évaluée au travers d'un exemple d'évaluation des dommages potentiels. Une maison individuelle en maçonnerie soumise aux mouvements de terrain a été étudiée à l'aide de l'expérimentation physique. Une campagne d'essais considérant les positions les plus sensibles par rapport à la cuvette d'affaissement est réalisée. L'évaluation du niveau de dommage a été réalisée à l'aide des mesures de déformations et des caractéristiques de fissures observées. La comparaison entre les méthodes conventionnelles et la méthode développée montre la pertinence de l'indicateur longueur des fissures, et cet indicateur peut être considéré comme un nouvel outil lors d'évaluation des dommages dans la pratique. Pour conclure, des recommandations opérationnelles ont été suggérées afin d'obtenir une meilleure estimation du niveau de dommages de la structureMasonry structures present a significant proportion of individual houses and are especially more vulnerable when subjected to ground movements. To deal with consequences of this problem, a test-platform has been developed in order to simulate ground movements and their effect on structure models on the surface. This thesis is based on a reduced physical model and develops damage assessment methods for masonry structures using physical modelling. Firstly, a small-scaled physical model under Earth's gravity (1g) has been developed to reproduce this phenomenon. This model of soil-foundation-masonry interaction has a scale factor of 1/40. The analogue soil consists of the Fontainebleau sand. The foundation part of the structure is made of liquid silicon and masonry walls are made from small wooden blocks. To measure displacements fields of the soil and the structure, a digital image correlation (DIC) technique is used. Discussions about the use of this technique when performing a test, especially the consideration of measurement errors, are also addressed. Secondly, we first assess the damage through conventional methods based on damage indicators and graphs. Then, new easy to use tools based on the DIC technique are proposed to carry out a more effective damage assessment. The first tool helps identify failure modes in the structure, based on the Winkler soil-structure interaction model. To do this, the inverse problem of soil-structure interaction is resolved, and the failure modes, based on internal forces, are identified. Then, a DIC-M model is proposed to reproduce the crack propagation in the masonry wall. The key point of this model consists in the simulation of the block movements in a discrete element system (DES). Consequently, cracks can appear easily, and then the crack identification and quantification become easier. More precisely, a new damage indicator related to the cumulated length of cracks allows to better quantify the damage and the cartography the cracks. The measurement uncertainty is determined by Monte-Carlo simulation. Thirdly, the performance of proposed tools is discussed through an example of assessing potential damages. An individual house in masonry subjected to ground movements was studied using physical experimentation. A test campaign related to the most sensitive positions of the structure with respect to the subsidence centre is performed. Damage assessment is conducted using deformation measurement and crack characteristics. The comparison between conventional and developed methods shows the relevance of the damage indicator related to the cumulated length of cracks, and this indicator can be considered as a new tool for damage assessment in practice. Finally, operational recommendations are suggested in order to obtain a better estimation of the damage level of the structure
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Libosvár, Marek. "Studie protipovodňových opatření v lokalitě Žabovřesky na Svratce v km 42,000 – 45,000." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2016. http://www.nusl.cz/ntk/nusl-240067.
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Diploma Thesis deals with the studies of flood protection measures in locality of Brno - Žabovřesky. The work is mainly focused on the calculation of flood flows (Q1, Q5, Q20, Q100 a Q100 neovlivněný) in the area of interest and to proposal flood control measures. Simulation calculations are performed using a coupled 1D / 2D model of the flow of surface water in the bed of the river and its flood area. The results of hydraulic calculations were within the framework the work processed in the form of maps depths, velocity and inundation. Curves levels were indicated in the longitudinal profiles of watercourses.
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Sköld, Olivia. "Analys av lägesosäkerheter hos fotogrammetriskt framställda DTM - en jämförelse mellan två programvaror." Thesis, Högskolan i Gävle, Samhällsbyggnad, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-32058.
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Idag blir användningen av drönare allt mer vanlig för dokumentation av markytor. Det är ett billigare alternativ för att dokumentera små och otillgängliga områden. Genom tekniken går det bland annat att framställa olika digitala modeller som representerar jordens yta. En sådan modell kan vara en terrängmodell (DTM) som är en modell av markytan exklusive vegetation, hus eller annat som befinner sig på marken. Modeller kan framställas genom flygdata såsom laserskannad (LiDAR-data) eller flygfotograferade data (flygbilder). För att framställa en digital modell från rådata används olika programvaror. Den här studien utvärderar två olika programvarors förmåga att framställa digitala terrängmodeller från flygbilder. Främst undersöks levererade osäkerheter och användarvänligheten i programmen. Referensdata som användes i denna studie tillhandahölls av Norconsult och samlades in vid ett projekt över Hammarbyhöjdsskogen i Stockholm, hösten 2018. Den data som erhölls från projektet till denna studie var flygbilder samt terrestra detaljmätningar. Programmen som studien utvärderar är UAS Master som både använder datorseende och fotogrammetriska metoder och SURE Aerial som använder datorseende. Genom studien visade det sig att fler än de ursprungliga programvarorna behövdes för att framställa de digitala terrängmodellerna och vidare jämföra dessa. En orsak var att UAS Master saknade förmågor att redigera och visa punktmoln i 3D-vy och vidare skapa en DTM. Detta resulterade i att använda Trimble Business Center för slutarbetet. En annan orsak var att SURE Aerial visade sig vara avsett för framställning av digitala ytmodeller (representation av den faktiska, synliga ytan). För att framställa en DTM av punktmolnet användes både Cloud Compare och Agisoft Photoscan (numera Metashape). Geo användes sedan för att ta ut höjdavvikelserna från modellen. Två slutsatser som kunde dras utifrån denna studie var: 1) trots de olika tillvägagångssätten erhölls snarlika resultat för marktypernas lägesosäkerheter för respektive programvara (asfalt: 0,039 m; grus: ca 0,040 m; gräs: ca 0,048 m), varpå alla blev godkända enligt HMK – Flygfotografering 2017; 2) SURE Aerial är ett enklare och snabbbare program men med UAS Master har man som användare bättre förståelse över processerna och erhåller bättre dokumentation.Drones have become a more and more frequent tool to document the surface of the ground, especially in smaller areas that otherwise are too expensive to observe by other means. This technology makes it possible to create digital terrain models (DTM) that represents the surface of the ground excluding vegetation, houses or other objects on the ground. These models can be created by laser scanned data (LiDAR-data) or aerial photogrammetry (aerial photos). In order to create a digital model from raw data are various software needed. This study aims to test two software’s ability to create digital terrain models from UAS photos. The software were evaluated by the uncertainties of the models, as well as the user-friendliness of each software. All data used in this study was collected by Norconsult for another project in 2018 and consist of UAS photos and data from terrestrial measurements. The softwares used in this study for comparison are UAS Master (using both computer vision and photogrammetric methods) and SURE Aerial (using computer vision). It turned out that additional use of software were needed to create DTMs that were comparable. UAS Master could not show or edit point clouds in 3D, because of this the software Trimble Business Centre had to be used. This program was also used to obtain height deviations. SURE Aerial on the other hand turned out to only be able to create digital surface models (models of the visible ground). The software Cloud Compare and Agisoft Photoscan (nowadays Metashape) were therefore used to create the DTM from the point cloud. The height deviations from the ladder DTM were obtained from the software Geo. Two conclusions could be drawn from this study: 1) the uncertainties of the different surface types were similar in the software despite the different ways to create the DTMs (asphalt: 0.039 m; gravel: 0.040 m; grass: 0.048 m). All of which meet the requirements according to HMK – Flygfotografering 2017; 2) SURE Aerial is a lot easier and quicker to work with but UAS Master give the user a lot more feedback in the way of documentation throughout the different processes.
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Servadio, Zarah. "Apports de l’imagerie à haute résolution spectrale et spatiale dans les bilans de volume et bilans radiatifs au Piton de La Fournaise." Thesis, La Réunion, 2011. http://www.theses.fr/2011LARE0020/document.
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La télédétection ouvre des perspectives nouvelles pour l’étude et la surveillance des volcans. Dans le cadre de cette thèse, différentes approches ont été abordées. L’imagerie satellite optique et thermique permet d’avoir une vue synoptique sur une large surface. La compréhension des changements d’état de surface est particulièrement importante dans le suivi de l’activité des volcans actifs. Plusieurs questions se posent : • Quels avantages offrent les satellites optiques d’observation de la Terre pour les calculs des volumes de lave émis ? • Quelles sont leurs limites ? • Les calculs de débits réalisés par télédétection sont-ils fiables ? • Quel est l’intérêt d’une approche multi-outils et multi-source ? Ces questions ont été abordées en prenant le Piton de la Fournaise pour cible. Plusieurs méthodes ont été mises en oeuvre et testées : 1) L’extraction automatique des contours de coulées de lave, 2) la création de modèle numérique d’élévation (MNE) par imagerie satellite, 3) le calcul de débits à partir d’images thermiques, 4) le suivi post éruptif d’une coulée par la modélisation de son refroidissement et la mesure des déformations observées in-situ. La plus-value de ce travail est la capacité de valider les résultats des modèles issus de la télédétection par des mesures in situ du fait de la proximité des sites étudiés. L’utilisation de ces techniques a permis d’obtenir des débits moyens d’écoulement des laves pour plusieurs éruptions et de suivre l’évolution topographique du volcan et de ses grandes structures. Les mesures thermiques par satellite fournissent le moyen de contraindre les variations du débit des éruptions dans le temps, tandis que les MNE ont permis d’obtenir un volume total dans le cas de coulées présentant de fortes épaisseurs. Grâce à ces techniques, il a été possible de définir deux types d’éruptions avec des évolutions semblables à celles observées sur différents volcans comme l’Etna (Italie) ou le Krafla (Islande). Les problèmes de nébulosité étant récurrent sur notre zone d’étude, la complémentarité des techniques est particulièrement intéressante pour obtenir une information fiable. Toutes les techniques utilisées dans cette thèse sont applicables à d’autres volcans ou à d’autres thématiquesRemote sensing opens new perspectives for the study and monotoring of volcanoes. In this thesis, different approaches were discussed. optical and thermal satellite imagery provides a synoptic view over a wide area. The understanding of surface state changes is particulary important in the monotoring of the activity of active volcanoes. Several, questions arise: • What advantages offer optical observation satellites of the Earth for calculations of lava volumes issues? • What are their limits? • Calculations of flow by remote sensing are reliable? • What is the interest of a multi-tool and multi-source approach? These issues were addressed by taking the Piton de la Fournaise to target. Several methods have been implemented and tested: 1) automatic extraction of the contours of flows of lava, 2) the cretion of numerical model of elevation (DEM) imaging satellite, 3) the calculation of flows from thermal images, 4) follow-up post eruptive flow modelling of cooling and the observed deformations in-situ measurement. The added value of this work is the ability to validate the results of remote sensing measurements from models because of the proximity of the sites studied in situ. The use of these techniques to obtain the average flow rates of lavas to several eruptions and follow topographic evolution of the volcano and its large structures. Satellite thermal measurements provide the means of forcing changes in the flow of eruptions over time, while Dems helped to obtain a total volume in the case of flows with high thicknesses. With these techniques, it was possible to define two types of erutions with changes similar to those observed on different volcanoes
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Vaišvila, Andrius. "Nenusistovėjusio tekėjimo reiškiniai Kruonio HAE reversiniame kanale ir jų modeliavimas." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2012. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2012~D_20120530_125628-26197.
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Darbe nagrinėjami nenusistovėjusio vandens tekėjimo reiškiniai, kurie atsiranda Kruonio HAE reversiniame kanale dėl netolygaus hidroagregatų veikimo juos paleidžiant ir stabdant. Tyrimų tikslas - nustatyti nenusistovėjusio tekėjimo dėsningumus Kruonio HAE reversiniame kanale ir jam artimiausioje Kauno marių dalyje. Tyrimų metodas – hidrodinamikos skaitmeninis modeliavimas MIKE21 aplinkoje. Hidrodinamikos modelyje panaudotas reversinio kanalo dugno skaitmeninis reljefo modelis, sudarytas stačiakampių gardelių tinklo (grido) pavidalu pagal naujausius batimetrinių matavimų rezultatus. Elementarių gardelių matmenys 5x5 m. Modelio pakraštinėms sąlygoms aprašyti pasirenkamos laiko funkcijos, kurios išreiškia kiekvieno HAE hidroagregato vandens debito kitimą laiko atžvilgiu įvairių modeliuojamų HAE darbo režimų scenarijuose. Kitoje modelio atviroje riboje nustatomas fiksuotas Kauno marių vandens lygis. Hidrodinamikos modeliavimo rezultatai išvedami ir užrašomi kiekvienu skaičiuojamojo laiko žingsniu, o jų analizė atliekama naudojant MIKE21 programų paketo įrankius.
Hidrodinamikos modeliavimo rezultatų tikslumui ir patikimumui įvertinti buvo atlikta modelio patikra (t.y. verifikavimas), kurioje panaudoti realiai išmatuotų vandens lygių dinamikos ir tėkmės vektorių lauko krypčių vizualinių stebėjimų rezultatai.
Analizuojant gautus modeliavimo rezultatus buvo nustatyti nenusistovėjusio vandens tekėjimo Kruonio HAE reversiniame kanale dėsningumai, kurie pasireiškia staigaus... [toliau žr. visą tekstą]This work deals with fluctuations in the water flow regime that occur in the outlet channel of the Kruonis Pumped Storage Plant and are produced by uneven running of hydrounits while starting and stopping them. Research purpose: to determine the patterns of fluctuations in the water flow regime that occur in the outlet channel of the Kruonis Pumped Storage Plant and the nearest part of Kaunas Lagoon. Research method: numerical modeling of hydrodynamics in the MIKE21 environment. A digital terrain model of the reverse channel bottom consisting of a rectangular grid network (grid), made following the latest bathymetric measurements, was used for the hydrodynamic model. The elementary grid cell dimentions in the model were 5x5 m. To describe the boundary conditions of the model, time functions which express the water flow rate changes over time of each hydrounit in different operating modes of the KPSP were chosen. The fixed Kaunas Reservoir water level was set in the model as the other open boundary. The results of the hydrodynamic modeling were output and recorded at each computational time step and their analysis was performed using MIKE21 software package tools. To evaluate the accuracy and reliability of the hydrodynamic simulation results, a verification of the model was performed, which used the results of visual monitoring of actually measured water level dynamics and flow vector field directions . Analyzing the findings of simulation, consistent patterns of the... [to full text]
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Lundmark, Johan, and Häggström Lukas Grönlund. "Utvärdering av digitala terrängmodeller framtagna med flygburen laserskanning och UAS-fotogrammetri." Thesis, Högskolan i Gävle, Samhällsbyggnad, GIS, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-27295.
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Over the last years there has been a rapid development in the UAS-technology (Unmanned Aircraft Systems) and today there are several UAS systems on the market. The fast development has led to differences in both price and capability of taking high-quality images between the systems. The purpose of this study was firstly to investigate how two UAS systems differ in the uncertainty of measurement while making digital terrain models, secondly, to investigate how different UAS systems cope with the laws and requirements that exist for producing digital terrain models for detail projection, SIS-TS 21144:2016 Table 6 level 1-3. A comparative study on two software’s creation of point clouds from picture data was also conducted. In this study, three digital models were made from one specific area. They were created with two different UAS-systems and laser scanning from an airplane. The models were compared and analysed using the RUFRIS method. The UASsystems used were a fixed wings Smartplanes S1C and a rotary wings Dji Phantom 4 PRO. The Smartplanes flew 174 m above the ground and the Dji Phantom 4 flew 80 m above the ground. The results from the study show that laser scanning from the airplane created the model with the lowest measurement uncertainty and met all the requirements for each separate type (asphalt, natural soil, grass and gravel) for detail projection according to SIS.TS 201144:2016 table 6 level 1-3. Additionally, the results show that the terrain model produced by the Dji Phantom 4 only met the requirements for asphalt where the mean deviation was 0,001 m. The results produced with “Smartplanes” met the requirements for asphalt and gravel where the mean deviations were -0,007 m and 0,017 m. The softwares PhotoScan and UASMaster were compared while creating point clouds from pictures taken by the Smartplanes. The results show that PhotoScan had the lowest uncertainty for asphalt, grass and gravel surfaces while UASMaster produced lower uncertainty for natural soil. The results indicate that airborne laser scanning should be the preferred method for collection of topographic data since it created lower measurement uncertainties than the other methods in this study. It is also possible to create digital terrain models with UAS for detail projection for asphalt and gravel surface in accordance with 21144:2016. Finally, it was concluded that the used software programs are showing differences in creating point clouds.De senaste åren har tekniken för Unmanned Aircraft System (UAS) utvecklats snabbt och idag finns flera system på marknaden. Ett resultat av den snabba utvecklingen är att de olika systemen skiljer sig åt, dels i pris men även i kapacitet. Syftet med studien var att undersöka hur olika UAS-system skiljer sig åt i mätosäkerhet vid framställning av digitala terrängmodeller, men även hur olika UAS-system står sig mot det regelverk som finns för framställning av digitala terrängmodeller vid detaljprojektering enligt SIS-TS 21144:2016 Tabell 6 klass 1-3. Ytterligare ett syfte med studien var att undersöka hur olika programvaror skiljer sig åt vid framställning av punktmoln från bilddata. I studien kontrollerades och jämfördes tre digitala terrängmodeller genererade över samma område med två olika UAS-system samt laserskanning från ett flygplan. Terrängmodellerna jämfördes mot kontrollprofiler framställda med RUFRIS-metoden. De olika UAS-systemen var en dyrare variant, Smartplanes S1C (fastavingar), och en billigare variant, Dji Phantom 4 PRO (roterande vingar). De tillämpade flyghöjderna för flygningarna var 174 m för Smartplanes och 80 m för Dji Phantom. Resultatet från studien visar att laserskanning från flygplanet uppnådde lägst mätosäkerhet och klarade samtliga krav för varje separat marktyp för detaljprojektering enligt SIS-TS 201144:2016 Tabell 6 klass 1-3. Marktyper som undersöktes var: asfalt, naturmark, gräs och grus. Vidare klarade terrängmodellen producerad med Dji Phantom endast kravet för asfaltsytor, där medelavvikelsen fastställdes till 0,001 m. Terrängmodellen producerad med Smartplanes klarade endast kraven för marktyperna asfalt och grus där medelavvikelsen fastställdes till -0,007 m respektive 0,017 m. Som en del i studien jämfördes programvarorna PhotoScan och UASMaster för framställning av punktmoln för bilder insamlade med Smartplanes S1C. Resultatet visar att PhotoScan uppnådde lägst mätosäkerhet för asfalt, gräs och grus medan UASMaster uppnådde lägst mätosäkerhet för naturmark. Studien visar att flygburen laserskanning borde vara en fortsatt föredragen metod för insamling av topografisk data då metoden resulterade i lägst mätosäkerheter i denna studie. Vidare visar studien att det är möjligt att framställa digitala terrängmodeller med UAS för detaljprojektering enligt SISTS 21144:2016 för asfalt- och grusytor. Dessutom konstateras att olika bearbetningsprogram skiljer sig vid framställning av punktmoln.
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Silva, Karla de Andrade e. "Análise da variabilidade espacial da precipitação e parâmetros hidrológicos em bacia experimental: estudo da transformação da chuva em uma pequena bacia hidrográfica urbana." Universidade de São Paulo, 2003. http://www.teses.usp.br/teses/disponiveis/18/18138/tde-16112016-093025/.
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A primeira parte deste trabalho consistiu na instalação de pluviógrafos e linígrafos e levantamento de eventos hidrológicos com a obtenção de dados da distribuição espacial de precipitações observadas e hidrogramas resultantes. Experimentos de infiltração de água no solo foram realizados a partir de infiltrômetro de disco a fim de caracterizar a variabilidade espacial da condutividade hidráulica na bacia, obtendo-se dois conjuntos de dados que mostraram ser lognormalmente distribuídos com médias iguais a 15,8 mm/h e 5,47 mm/h. Estudo teórico foi conduzido na segunda parte do trabalho compreendendo o desenvolvimento de modelo hidrológico. A concepção do modelo parte da premissa de que toda a área da bacia possa ser representada por células derivadas de um modelo numérico de terreno (MNT), especificando-se em cada célula o equacionamento hidráulico-hidrológico. As heterogeneidades do solo e da precipitação foram estudadas através de simulação do modelo considerando-se distribuições espaciais diferentes para a condutividade hidráulica saturada e eventos de chuva. Os resultados mostraram que as diferenças entre as vazões de pico podem ser maiores que 100% , considerando-se graus de resolução máximo e mínimo quanto à precipitação, e reafirmaram o consenso de que o conhecimento da distribuição espacial da chuva é fundamental na calibração de modelos hidrológicos distribuídos.In first part of this work consists on the installation of pluviographic, water-height graphs and surveying of hydrological events with obtained data from spatial distribution of precipitation observed and resultant hydrograms. Experiments of water infiltration in the soil were done by an infiltrometer disc to characterize the spatial variability of hydraulic conductivity and the losses of infiltration in the basin obtaining two sets of data that showed to be lognormally distributed in average equal to 15.8 mm/h and 5.47 mm/h. A theoric study was conduced in the second part of work comprehending the development of hydrologic model distributed. The conception of the model proceed from the premise that allbasin area can be represented by cells derived from a Digital Terrain Model (DTM) specifying in each cell the hydraulic equation - hydrologic. The soil heterogeneity and the precipitation were studied by model simulation considering spatial distributions different to the hydraulic conductivity satured of the soil and to pluvial events. The results pointed out the differences among peak outflow can be more than 100% considering minimum and maximumresolution degrees as the precipitation and affirmed the consensus that the acquaintance of the pluvial spatial distribution is fundamental in the adjustment of hydrologic models distributed.
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Sarrazin, Benoit. "MNT et observations multi-locales du réseau de drainage d'un petit bassin versant rural dans une perspective d'aide à la modélisation spatialisée." Thesis, Grenoble, 2012. http://www.theses.fr/2012GRENU042/document.
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Le fonctionnement hydrologique des petits bassins versants ruraux de quelques km² à régime intermittent est complexe car de nombreux processus affectent le cheminement des eaux de surface. Il en résulte une variabilité de la densité de drainage et de la dynamique de l'écoulement au sein du réseau hydrographique. Cette dynamique de fonctionnement est peu prise en considération du fait des difficultés d'ordres techniques et économiques pour suffisamment observer les mouvements de l'eau à la surface. Or, c'est une information essentielle pour décrire la connectivité hydrologique du bassin qui représente la distribution spatiale et temporelle des surfaces contributives à l'écoulement par leur connexion au réseau de drainage. De telles connaissances seraient utiles pour traiter la question de la séparation entre production et transfert effectuée dans les modèles hydrologiques, avec la perspective de proposer des simulations plus justes physiquement. L'objectif de la thèse est de proposer des approches spatiales pour mieux intégrer la dynamique de fonctionnement du réseau de drainage en lien étroit avec la réponse hydrologique du bassin. Le Mercier (7 km²) est le site expérimental situé en tête du bassin versant de l'Yzeron (142 km²) localisé à l'ouest de l'agglomération lyonnaise. Ce bassin sur socle cristallin est composé essentiellement de surfaces agricoles et de forêts. Son fonctionnement hydrologique est affecté par l'existence de zones humides contributives. Un réseau de routes et de fossés anthropiques s'ajoute aux talwegs naturels. Les méthodes développées relèvent de deux approches : (1) la microtopographie issue d'un MNT LiDAR (Light Detection and Ranging) permet d'identifier et décrire des extensions fonctionnelles du réseau de drainage d'une part au niveau des linéaires artificiels avec un apport minimal de données externes, et d'autre part au niveau des talwegs naturels en distinguant la présence ou l'absence d'un chenal de drainage, signe d'un potentiel d'écoulement concentré. (2) Un dispositif de 18 capteurs limnimétriques est mis en œuvre pour assurer un suivi permanent de la réponse hydrologique par emboitement de stations au sein du réseau hydrographique. Cette observation « multi-locale » permet de mesurer l'évolution de la densité de drainage, d'identifier localement la hiérarchie des facteurs qui affectent la réponse et de distinguer différentes dynamiques de transfert dans le réseau de drainage. Les résultats des approches par la microtopographie et par observations multi-locales aident à identifier des régions du bassin au comportement différent. Ils permettent notamment de mieux comprendre les interrelations entre occupation du sol et processus hydrologiques, voire géomorphologie et processus. Ces résultats valident donc l'intérêt du capteur LiDAR et celui d'un dispositif in situ souple et adaptable pour proposer un « pattern de drainage » réaliste en limitant le recours au terrain. Enfin, ce pattern décrivant la tendance d'organisation spatiale des écoulements, est paramétré dans une fonction de transfert géomorphologique calculée sur la base des cheminements fournis par un MNT. L'usage de cet outil constitue une ébauche mais conforte l'idée d'un couplage entre le pattern de drainage et la réponse du bassin versant dans des conditions d'intensité pluvieuse soutenue et d'humidité modérée pour expliquer la réponse rapide du bassin. L'ensemble des résultats justifie donc la mise en avant de la nature transitoire du réseau de drainage pour paramétrer des modèles spatialisés avec la perspective d'améliorer leurs capacités prédictivesHydrological functioning of small temporary catchments depends on several processes governing transfer from surface water paths. As a result flow dynamics and drainage density are highly variable in space and time. But this complex dynamic is not enough taken into account because of technical and economical limitations. However, it is essential to describe hydrological connectivity as a spatial and temporal pattern of contributive areas to the drainage network. Get this pattern may facilitate the conceptual distinction between production and transfer functions to improve spatially distributed models. The aim of the study is to develop methods to describe spatial and temporal patterns of the drainage network in relation to catchment hydrological responses. The Mercier headwater catchment (7 km²) is located into the Yzeron catchment near Lyon (France). The land use is principally composed of agricultural plots and forested areas. The hydrographical network consists of natural thalwegs and many roadside ditches and agrarian ditches. Both approaches are developed for this purpose: first, the micro-topography from a LiDAR DEM helps to describe potential flow lengths from drainage network extensions during rainfall events. On the one hand, main artificial ditches are mapped from the DEM with minimal corrections from ancillary data. On the other hand, channelized or unchannelized reaches are located from the DEM into the natural thalwegs. Second, a water level sensor device is set up to record hydrological response from 18 stations located in nested sub-catchments into the hydrological network. These synoptic measurements are used to estimate temporal changes in drainage density, to analyze local hydrological functioning, or to describe flood propagation to the outlet. Results from both approaches lead to the identification of specific behaviors inside the hydrological network controlled by functional thresholds. These patterns help to better understand the relationship between land use and hydrological processes. The results also show the interest of LiDAR DEM and the suitability of adaptable distributed measurements as a substitute to heavy in situ studies for the identification of drainage patterns. Finally, to test the assumption of a gradual drainage network extension during a rainfall event, a simplified drainage pattern is processed into a geomorphological transfer function. This tool is fairly easy to set and is used to initiate an association between local hydrological knowledge and global catchment response. Both approaches lead to conclude that various drainage pattern must be integrated into spatially distributed models according to hydrological conditions, rather than a single hydrological network
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Do, Hiep-Thuan. "Extensibilité des moyens de traitements pour les données issues des vastes systèmes d'informations géographiques." Phd thesis, Université d'Orléans, 2011. http://tel.archives-ouvertes.fr/tel-00660083.
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Cette thèse s'inscrit dans le cadre de l'évolution des Systèmes d'Informations Géographiques (SIG) et de leur capacité à répondre à des problématiques environnementales qui s'expriment de manière globale et transversale. Dans un contexte ou l'information géographique est en plein essor et où la quantité de données disponible ne cesse de croitre, le besoin en terme d'outil d'aide a la décision n'a jamais été aussi fort. Cette étude s'attache tout particulièrement au cadre de la résolution de problématiques liées à l'eau et l'environnement lorsque les données deviennent trop volumineuses pour être traitées par des moyens de calculs séquentiels classiques. Nous proposons une plateforme de calculs répartis sur une grappe d'ordinateurs qui parallélise le calcul de la délimitation des bassins versants des grands fleuves et la détermination des flots d'accumulation. A cette fin nous introduisons une technique de calcul parallèle d'une forêt d'arbres couvrants minimums représentant le parcours de l'eau de chaque point du Modèle Numérique de Terrain (MNT) vers la mer. Cette technique débute par une délimitation des cuvettes (ensemble de points allant vers le même minimum local) contenues dans le MNT. Ensuite une hiérarchie de déversement des cuvettes les unes dans les autres est construite jusqu'à obtenir les bassins versants des fleuves. L'étude se poursuit par la description d'un algorithme parallèle pour le calcul très couteux des flots d'accumulation en chaque point du MNT. Enfin cette thèse présente une version ≪out-of-core≫ de nos algorithmes parallèles afin d'étendre la portée de nos travaux a des grappes de dimensions modestes qui ne peuvent pas charger en mémoire la totalité du MNT traite.
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Kassouk, Zeineb. "Apports de la télédétection, de la géomatique et du modèle numérique de terrain topo-bathymétrique intégré pour l'aide à la gestion des milieux humides littoraux : application à l'estuaire de la Rance (Ouest de la France) et au lac Ichkeul (Nord de la Tunisie)." Thesis, Paris Est, 2009. http://www.theses.fr/2009PEST1069.
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Les milieux humides littoraux sont des systèmes écologiques complexes qui résultent des interactions entre des processus hydrologiques, géomorphologiques et biologiques. Ils sont généralement très convoités pour leurs intérêts tant écologiques qu’économiques. Plusieurs approches ont été employées pour mieux comprendre leurs évolutions spatiotemporelles en fonction de perturbations aussi bien naturelles qu’anthropiques qu’ils subissent. Les outils de la télédétection et des potentialités des Systèmes d’Informations Géographiques (SIG) ont été largement développés. Ainsi dans cette étude, on propose une approche cartographique de deux milieux humides, basée sur la classification orientée-objet des photographies aériennes et les images satellitaires multidates et multi-résolutions et utilisant un modèle numérique de terrain (MNT) topo-bathymétrique intégré pour étudier ces perturbations. Cette approche a permis d’étudier l’évolution de deux milieux humides situés dans deux contextes climatiques et géographiques différents qui sont l’estuaire de la Rance situé à l’ouest de la France dans un contexte tempéré océanique et ayant subi la construction d’un barrage marémoteur (aménagement hydraulique majeur) en 1966. Le deuxième milieu est le lac de l’Ichkeul situé au nord de la Tunisie, un des milieux humides les plus importants de la méditerranée qui est sujet à des aménagements hydrauliques continus et fortement dépendant des perturbations climatiques. Pour l’exemple de l’estuaire de la Rance, l’étude des évolutions géomorphologiques a été effectuée en utilisant des comparaisons du MNT intégré réalisé dans le cadre de cette étude à partir de données bathymétriques et topographiques acquises avant la construction du barrage marémoteur avec des données bathymétriques acquises en 1982 puis en 1998. On a par exemple confirmé localement les évolutions de la topo-bathymétrie. On révèle la déviation du chenal principal, ainsi que l’érosion des zones situées à l’aval à proximité du fort courant ou bien au contraire leur sédimentation dans les zones protégées de l’action des courants. L’étude de l’évolution de la végétation du schorre (herbus) a été effectuée par deux méthodes : une cartographie surfacique multidate de la végétation à partir des photographies aériennes acquises en 1953, 1961, 1966, 1978, 1982, 1996 et une orthophotographie aérienne acquise en 2002 et une cartographie de la végétation du schorre faite en exploitant les capacités de segmentation des images à haute- résolution spatiale offertes par la méthode de classification orientée-objet et le modèle topobathymétrique intégré. Cette étude comparative a montré que la surface globale du schorre a augmenté suite à la mise en place du barrage marémoteur, une tendance à l’équilibre des surfaces est observée depuis 1978. Un nouvel équilibre global s’est instauré dans l’estuaire douze ans après la construction du barrage marémoteur. Dans le cas de l’étude du milieu humide du lac Ichkeul, correspondant au deuxième exemple étudié ici, la méthode de classification orientée-objet a été utilisée pour la cartographie de l’évolution de la végétation en utilisant des images satellitaires multisources, multi-résolutions et multidates (MSS-Landsat (1972), TM-Landsat (1987), ETM+ Landsat (2001) and Aster-Terra (2007)) et le MNT topobathymétrique intégré. Cette méthode a permis d’identifier les principales communautés végétatives caractéristiques des marais de l’Ichkeul, à savoir la communauté à base de Sarcocornia fruticosa, la communauté à base d’Hordeum Marinum, la communauté à base de Visnaga Daucoides et la communauté à base de Bolboschoenus. L’évolution morphologique du lac est étudiée en comparant le MNT topo-bathymétrique intégré réalisé à partir de données topographiques et bathymétriques acquises en 2003 avec des données bathymétriques acquises en 1967, 1983, 1986 et 1993. Elle fait apparaître le déplacement des zones d’accrétion et de sédimentation dans le lac suite aux aménagements hydrauliques ainsi on relève : (1) une érosion dans la partie est du lac entre 1967 et 1982 (2) un engraissement aux alentours de l’écluse entre 1982 et 1986 et (3) un déplacement des zones les plus profondes vers le sud-ouest du lac et un comblement de la partie du lac située au pied (nord-est) du Djebel Ichkeul depuis 1993. Cette étude a montré que les modifications drastiques des apports d’eau et les perturbations climatiques constituent les principales causes des altérations physiques du milieu humide de l’Ichkeul. Le retour à une dynamique naturelle est loin d’être atteint et dépend fortement des interventions humaines et des facteurs climatiques. La méthode utilisée ici a permis d’étudier deux milieux humides différents et leurs évolutions en se basant sur le degré de complexité de chacun d’eux ainsi que sur le type de la perturbation qu’ils subissent, permettant ainsi de différencier les tendances d’évolution actuelles (stabilité ou évolution) de chaque milieu. L’étude du contexte géomorphologique associant (1) les évolutions de la végétation des milieux humides, et (2) l’exploitation de la classification orientée-objet, multidates et multi-résolutions, à partir d’une approche intégrée de télédétection utilisant les SIG présente par conséquent un fort potentiel pour proposer et optimiser les modes de gestion adaptés aux objectifs de préservation des zones humides et de développement durable en généralCoastal wetlands are an important component of the natural environment of the coastal zone. Wetlands are affected by hydrologic and geomorphic controls that must be taken into consideration when attempting to understand wetland responses to disturbance, provide information for better wetland management, or aid in the restoration of lost habitat. The functioning of coastal wetlands is a result of complex linking of distinct biological, geomorphologic and human factors interacting in varying scales. Natural water circulation and water quality can altered the natural behaviours of that ecosystem. Remote sensing techniques (pixel based classification methods) and geographic information system are well used herein in monitoring coastal wetlands areas. But they are confronted to many difficulties such as combing together both onshore and offshore data and process and discriminate wetlands from uplands areas. The overall goal of our study is to develop improved methods for wetland monitoring and management in two cases studies those are located in different areas and climate zones, which are : - The Rance estuary in Western France is subject to many morphologic and biological modifications due to the management of the Rance tidal power station since 1966. The construction had required isolating completely open sea from the Rance estuary for more three years. Since that time, some environmental changes took place in the Rance estuary area, such as modifications and disappearance of sandbanks in some areas, leading to a new equilibrium since 1978. - The Ichkeul Lake in the North of Tunisia is one of the most important wetlands in the Mediterranean region. However, the decreasing of water discharge into the lake caused by the damming of three of the six major rivers feeding the lake coincided with severe drought periods, restricting supplies of fresh water, and modifying saltmarsh vegetation communities and other significant wetland degradation. Furthermore, one specific objective of our work is to investigate the capabilities of the object oriented classification methods combined to integrated topographic-bathymetric digital terrain model in those areas. In the case study of the Rance estuary morphological evolution after the settlement of the tidal power station is done by the comparison of the integrated Topographic-Bathymetric Digital Terrain Model (DTM), combining the 1953 bathymetric data, and 1957 topographic ones, with bathymetric profiles acquired in 1982 and 1998. It shows that increase of topography corresponding to accretion is frequently observed in coves characterised by low current energy. In contrast, the places exposed to high currents present generally strong eroded features, which decrease and erode the topography. The meandering of channels has also observed through time. The use of object-oriented classification of aerial photographs, acquired between 1953 and 2002 and the integrated DTM of salt marshes area in the Rance estuary, enhanced their surface regression from 1953 to 1978. It shows their stability since, due to hydrologic modifications induced in the Rance estuary after the tidal power plant management such us the change of tidal range and the period of slack water. In the case study of the Ichkeul, the application of object-oriented classification approach to identify Ichkeul wetland vegetation is based on the following multi-spectral imagery: the MSSLandsat (1972), TM-Landsat (1987), ETM+ Landsat (2001) and Aster-Terra (2007) acquired in growth period of vegetation. Results show the declining of vegetation communities in Ichkeul wetlands exposed to alternative fresh and salt-water diversion. Sarcocornia fruticosa, communities, Hordeum communities are the largest units in the study area. The Bolboschoenus communities is absent in the 1987 and 2001 vegetation maps. This is conformed by previews studies witch are showing that due to dry periods and rivers damming the Bolboschoenus disappeared for many years. The monitoring the lake Ichkuel sedimentation process was done by comparison of five sets of bathymetric data taken in 1967, 1983, 1986, 1993 and 2003. It shows the alteration of sedimentation process in the Ichkeul Lake as behaviour of the coastal zone after the settlement of dams. To conclude, owing to difference of climatic and hydrodynamic characteristics the responses of coastal wetland to natural and human will vary according to difference of their geomorphology and ecology. The Rance estuary seams to have new ecology balance ten years after the settlement of the tidal power station. However, the Ichkeul Lake is still affected by anthropogenic and climatic factors. Therefore, the used methodology provides detailed information on wetland vegetation and adjacent land-use/land-cover types in schorre wetland areas in the cases of the Rance estuary, and the Ichkeul marches areas. This technique is combining both integrated DTM and remote sensing data that is a useful tool for wetland vegetation monitoring and for resolve some major classification confusions that occur in such wetland areas
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Pieczonka, Tino. "Untersuchung und Visualisierung von Gletschervolumenänderungen im Tarim-Einzugsgebiet, Zentralasien, unter Verwendung multi-temporaler digitaler Geländemodelle." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2018. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-234998.
Full textAbstract:
Das aride Tarim-Becken im Nordwesten Chinas unterliegt Umweltveränderungen, die durch rapide Ausbreitung bewässerter Landwirtschaft sowie Klimawandel angetrieben sind. Während im Oberlauf in den letzten 50 Jahren ein Abflussanstieg beobachtet wurde, haben landwirtschaftliche Aktivitäten im Mittel- und Unterlauf zur Wasserknappheit und der drastischen Verkürzung des endorheischen Flusses geführt. Der Abfluss des Tarim, dessen Hauptzufluss der in Kirgistan entspringende Aksu-Fluss darstellt, wird zu einem großen Teil aus Schnee- und Gletscherschmelze in den oberen Gebirgseinzugsgebieten des Tien Shan gespeist. Da die Unterlieger von dem Wasser des Tarim zur Bewässerung in der Landwirtschaft abhängig sind, sind das Wissen über den Beitrag der Gletscherschmelze zum Abfluss sowie das Wissen über mögliche zukünftige Änderungen der Gletschermasse von großer Relevanz.
Zahlreiche Studien beschränken sich oftmals nur auf die Betrachtung der Gletscherfläche, deren Änderung jedoch keine direkten Rückschlüsse auf etwaige Massenänderungen zulässt und zudem nur ein indirektes Signal für Klimaänderungen darstellt. Weiterführende Studien, welche zusätzlich Gletschermassenänderungen im Aksu-Einzugsgebiet untersuchen, haben häufig nur lokalen Charakter. Regionale Studien zu Massenänderungen, welche ganze Einzugsgebiete und Gebirgsketten umfassen, finden sich mehrheitlich für die letzte Dekade durch die Verfügbarkeit laseraltimetrischer Höhendaten und gravimetrischer Messungen, wobei letztere durch hohe Unsicherheiten gekennzeichnet sind. Um jedoch Aussagen hinsichtlich der zeitlichen Entwicklung der Gletscher treffen zu können, widmet sich die Arbeit insbesondere der Untersuchung von Gletschermassenveränderungen seit den 1970er Jahren unter Verwendung deklassifizierter amerikanischer Satellitenbilddaten, SRTM-Daten sowie SPOT-5-Stereodaten.
Zur Ableitung geodätischer Gletschermassenbilanzen wurden Daten der Mapping Camera (MC) des Hexagon-Satelliten aus den Jahren 1973–1976 stereoskopisch ausgewertet und mit Daten der SRTM-Mission aus dem Jahr 2000 und SPOT-5-Stereodaten aus dem Jahr 2009 verglichen. Die Ableitung geodätischer Massenbilanzen aus multi-temporalen Geländemodellen erforderte deren Co-Registrierung auf das als SRTM gewählte Master-Modell. In einem zweistufigen Verfahren wurden Verkippungen über eine globale Trendfläche und horizontale Lagefehler über eine analytische Beziehung zwischen Oberflächenneigung, Orientierung und der entsprechenden Höhendifferenz unter Einbeziehung nicht-glazialer Pixel minimiert. Die Eindringtiefe des SRTM-C-Bands wurde mittels ICESat-Daten mit 2,2 m abgeschätzt und bei der Differenzbildung berücksichtigt. Zur Bereinigung der Differenzbilder zwischen den Geländemodellen wurde ein höhenbasierter Ansatz entwickelt, welcher eine abnehmende Varianz der Höhendifferenzwerte vom Ablations- zum Akkumulationsgebiet annimmt. Dieser Ansatz stellt eine deutlich realistischere Annahme im Vergleich zur oftmals verwendeten Nullannahme dar, welche von keinen Veränderungen in den Akkumulationsgebieten ausgeht. Die Gletscher im Aksu-Einzugsgebiet zeigten im Ergebnis einen Massenverlust von 0,35±0,34 m w.e./a im Zeitraum 1975–1999, was dem globalen Durchschnitt für diese Periode entspricht. In den Jahren 1999 bis 2009 wurde indes eine Abnahme des Massenverlusts (0,23±0,19 m w.e./a) festgestellt, was möglicherweise auf eine Zunahme des Niederschlags in der letzten Dekade zurückzuführen ist. Zudem zeigte sich, dass schuttbedeckte Gletscher, deren Schuttauflage ab einer Dicke von etwa 2 cm einen hemmenden Einfluss auf die Abschmelzrate hat, signifikant an Masse verloren haben bei gleichzeitig nur relativ geringer Flächenabnahme. Insgesamt wies die räumliche Verteilung der Massenänderungen eine starke Heterogenität auf, mit zunehmender Tendenz von Osten nach Westen und von den Innen- zu den Außenbereichen des Zentralen Tien Shan. Zusätzlich konnten zahlreiche, zuvor in der Literatur nicht benannte, surgende Gletscher identifiziert werden. Der durch Eismassenverlust induzierte Anteil am Gesamtabfluss des Aksu wurde im Ergebnis mit circa 20% ermittelt.
Neben der Oberflächenneigung sind, in einfachen Modellen zur Eisdickenabschätzung, die basale Scherspannung und der Anteil basalen Gleitens an der Oberflächengeschwindigkeit Haupteinflussfaktoren. Anhand gemessener Eisdicken, fernerkundlich abgeleiteter Gletscherfließgeschwindigkeiten und der Oberflächenneigung, als Näherung der Neigung des Gletscherbetts, konnte ein empirischer Zusammenhang zur Abschätzung des Anteils basalen Gleitens abgeleitet werden. Die Eisdickenabschätzung für die vier größten Gletscher des Zentralen Tien Shan erfolgte im weiteren Verlauf durch Anwendung von Glen’s Fließgesetz, unter Annahme laminaren Fließens. Die Ergebnisse weisen für die betrachteten Gletscher mittlere Dicken von 70 m bis 140 m für deren schuttbedeckte Gletscherzungen auf. Diese Werte liegen teilweise deutlich unter denen bisheriger Studien, welche von einer globalen Scherspannung für den gesamten Gletscher oder einem konstanten Anteil basalen Gleitens ausgehen. Im Vergleich zu vorhandenen Eisdickenmessungen konnte durch die lokale Abschätzung der basalen Geschwindigkeit die mittlere Abweichung von zuvor mehr als 200 m auf etwa 50 m reduziert werden. Durch Einbeziehung der in der Arbeit ermittelten geodätischen Gletschermassenbilanzen wurde der relative Volumenverlust seit den 1970er Jahren mit 6% bis 28% quantifiziert, welcher deutlich unter dem schuttfreier Gletscher innerhalb Hochasiens liegt.
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WU, CHENG-HSUAN, and 吳承軒. "High Performance Flood Simulation with Precise Digital Terrain Model." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/4uctde.
Full textAbstract:
碩士國立臺北科技大學
土木工程系土木與防災碩士班
107
Today, high Performance Flood Simulation have developed in many cities. In order to hourly forecast flooding for next three hours, the resolution of the Digital Elevation Model (DEM) in Flood module are usually 20m and 40m. With the evolution of computing devices, there is a tendency for Flooding Simulation with precision terrain. Hydro Digital Elevation Model (HyDEM) has been proposed to consider detailed terrain. Objects affecting water flooding on the ground will be retained, while those allowing water to penetrate will be shown as the elevation of the ground to make HyDEM much closer to reality. However, flooding simulation often requires lengthy computing time when using precise terrain, HyDEM has not been applied to real-time flood forecasting. Balancing computing time and flooding forecasting timeliness with limited hardware resources and software limitation is important. In the 2D flood module, the amount of grids, which is influenced by calculation area and grid resolution, is a key factor in computing time. In this study, the accuracy of the simulation is taken as a priority through adjusting calculating area to control the number of grids. Instead of using high resolution DEM in the entire basin, partial high resolution DEM in high risk area combine with low resolution DEM, will reduce lot of computation and save computing time. In this study, adaptive partitioning algorithm was proposed for improving simulation accuracy by the combination of high and low resolution of grids. Size of precise digital terrain area was resolved by changing threshold value, which is determined simulating flooding frequency and depth, to make computing time within a limited time. Simulating numerous flooding with flooding module in Dongmen River Basin in Taoyuan City, high-risk flooding areas are defined. With the multi-grid function which was used in high-risk flooding areas in SOBEK, configuration of precise terrain which could keep the computing time within the forecasting timeliness would be found out. The results show that the computing time vary with threshold value, indicating that this method can be used to find the appropriate terrain configuration in different situation.
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Chou, Yi-Chun, and 周怡君. "Simulation of Watershed Potential Landslides Using Digital Terrain Model." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/n46f39.
Full textAbstract:
碩士逢甲大學
土木及水利工程所
90
Landslide which caused by high-intensity rainfall has become an important factor of triggering debris flow. In this study, by stability theory and digital terrain model (DTM) data, wetness character and riverbed physical character, we can establish slope stability model and result in critical angle of failure. With landslide site, landslide slope and landslide area, the above three character can estimate the model accuracy. As results, the simulated hillslope failure site and failure slope matches will with the model in Nan-Ping-Keng, Jun-Ken-Kou, Er-Bu-Keng, San-Bu-Keng, Feng-Qiu in NanTou County after Tao-Zhi typhoon and its failure critical angle result between . Although the simulate failure landslide area has rater low accuracy, and lager than the actual value after Tao-Zhi typhoon, but it indicates that the above five area still has a great deal of landslide failure potential, and the occur of debris flow is relative high.
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Lan, Shyh-Cherng, and 藍士呈. "Fractal and Spatial Variation Analysis of Digital Terrain Model." Thesis, 1996. http://ndltd.ncl.edu.tw/handle/51261077674570346960.
Full textAbstract:
碩士國立臺灣大學
農業工程學系
84
Many hydrologic models nowadays use require spatially distributed data to derive watershed characteristics . Among these spatial data , DTM is increasingly importantin delineating subwatersheds ,defining flow paths , calculating slopes and 40m*40m grid areas . It is necessary to investigate the suitability of deriving hydrologic parameters form DTM through the analyses of scale invariance and spatial variability. DTM proflies along different directions of the Feitsuei Reservoir watershed located in northern Taiwan were considered fractional Brownain random field. Spatial variability of along each profile is characterized by its variogram. In our normalized variogram of different profiles were established and compared. No anisotropic spatial variability of elevation was found for the watershed. The effect of scale is investigated by resampling while keeping the suppory of the data unchange. Original DTM data were resampled at different spatial sampling intervals and use for study of scale invariance of elevation variability. Fractal dimension of the original and resampled DTM data are identical indicating the existence of scale invariance, thus,hydrologic parameters derived from DTM data can be used in distributed hydrological models .